classroom_app/classroom_app/ViewController.swift

//
//  ViewController.swift
//  classroom_app
//
//  Created by Dev Mac 1 on 06/04/2026.
//

import Cocoa
import QuartzCore
import WebKit
import AuthenticationServices
import StoreKit

private enum SidebarPage: Int {
    case joinMeetings = 0
    case photo = 1
    case enrolled = 2
    case teaching = 3
    case settings = 4
}

private enum ZoomJoinMode: Int {
    case id = 0
    case url = 1
}

private enum SettingsAction: Int {
    case restore = 0
    case rateUs = 1
    case support = 2
    case moreApps = 3
    case shareApp = 4
    case upgrade = 5
    case privacyPolicy = 6
    case termsOfServices = 7
}

private enum PremiumPlan: Int {
    case weekly = 0
    case monthly = 1
    case yearly = 2
    case lifetime = 3
}

private enum PremiumStoreProduct {
    static let weekly = "com.mqldev.classroomapp.premium.weekly"
    static let monthly = "com.mqldev.classroomapp.premium.monthly"
    static let yearly = "com.mqldev.classroomapp.premium.yearly"
    static let lifetime = "com.mqldev.classroomapp.premium.lifetime"

    static let allIDs = [weekly, monthly, yearly, lifetime]

    static func productID(for plan: PremiumPlan) -> String {
        switch plan {
        case .weekly: return weekly
        case .monthly: return monthly
        case .yearly: return yearly
        case .lifetime: return lifetime
        }
    }

    static func plan(for productID: String) -> PremiumPlan? {
        switch productID {
        case weekly: return .weekly
        case monthly: return .monthly
        case yearly: return .yearly
        case lifetime: return .lifetime
        default: return nil
        }
    }
}

@MainActor
private final class StoreKitCoordinator {
    enum PurchaseOutcome {
        case success
        case cancelled
        case pending
        case unavailable
        case alreadyOwned
        case failed(String)
    }

    private(set) var productsByID: [String: Product] = [:]
    private(set) var activeEntitlementProductIDs: Set<String> = []
    private(set) var lastProductLoadError: String?
    var onEntitlementsChanged: ((Bool) -> Void)?

    var hasPremiumAccess: Bool { !activeEntitlementProductIDs.isEmpty }
    var hasLifetimeAccess: Bool { activeEntitlementProductIDs.contains(PremiumStoreProduct.lifetime) }
    var activeNonLifetimePlan: PremiumPlan? {
        activeEntitlementProductIDs
            .compactMap { PremiumStoreProduct.plan(for: $0) }
            .filter { $0 != .lifetime }
            .max(by: { $0.rawValue < $1.rawValue })
    }

    private var transactionUpdatesTask: Task<Void, Never>?

    deinit {
        transactionUpdatesTask?.cancel()
    }

    func start() async {
        if transactionUpdatesTask == nil {
            transactionUpdatesTask = Task { [weak self] in
                await self?.observeTransactionUpdates()
            }
        }
        await refreshProducts()
        await refreshEntitlements()
    }

    func refreshProducts() async {
        do {
            let products = try await Product.products(for: PremiumStoreProduct.allIDs)
            productsByID = Dictionary(uniqueKeysWithValues: products.map { ($0.id, $0) })
            lastProductLoadError = nil
        } catch {
            productsByID = [:]
            lastProductLoadError = error.localizedDescription
        }
    }

    func refreshEntitlements() async {
        let previousHasPremiumAccess = hasPremiumAccess
        var active = Set<String>()
        for await entitlement in Transaction.currentEntitlements {
            guard case .verified(let transaction) = entitlement else { continue }
            guard PremiumStoreProduct.allIDs.contains(transaction.productID) else { continue }
            if Self.isTransactionActive(transaction) {
                active.insert(transaction.productID)
            }
        }
        // Some StoreKit test timelines can briefly report empty current entitlements
        // even though a latest verified transaction exists for a non-consumable.
        // Merge in latest transactions to keep launch access state accurate.
        for productID in PremiumStoreProduct.allIDs {
            guard let latest = await Transaction.latest(for: productID),
                  case .verified(let transaction) = latest,
                  Self.isTransactionActive(transaction) else { continue }
            active.insert(productID)
        }
        activeEntitlementProductIDs = active
        let newHasPremiumAccess = hasPremiumAccess
        if newHasPremiumAccess != previousHasPremiumAccess {
            onEntitlementsChanged?(newHasPremiumAccess)
        }
    }

    func purchase(plan: PremiumPlan) async -> PurchaseOutcome {
        let productID = PremiumStoreProduct.productID(for: plan)

        if activeEntitlementProductIDs.contains(productID) {
            return .alreadyOwned
        }

        guard let product = productsByID[productID] else {
            await refreshProducts()
            guard let refreshed = productsByID[productID] else {
                if let lastProductLoadError, !lastProductLoadError.isEmpty {
                    return .failed("Unable to load products: \(lastProductLoadError)")
                }
                let loadedIDs = productsByID.keys.sorted().joined(separator: ", ")
                let debugIDs = loadedIDs.isEmpty ? "none" : loadedIDs
                return .failed("Product ID not found in StoreKit response. Requested: \(productID). Loaded IDs: \(debugIDs)")
            }
            return await purchase(product: refreshed)
        }

        return await purchase(product: product)
    }

    func restorePurchases() async -> String {
        do {
            try await AppStore.sync()
            await refreshEntitlements()
            if hasPremiumAccess {
                return "Purchases restored successfully."
            }
            return "No previous premium purchase was found for this Apple ID."
        } catch {
            return "Restore failed: \(error.localizedDescription)"
        }
    }

    private func purchase(product: Product) async -> PurchaseOutcome {
        do {
            let result = try await product.purchase()
            switch result {
            case .success(let verificationResult):
                guard case .verified(let transaction) = verificationResult else {
                    return .failed("Purchase verification failed.")
                }
                await transaction.finish()
                await refreshEntitlements()
                return .success
            case .pending:
                return .pending
            case .userCancelled:
                return .cancelled
            @unknown default:
                return .failed("Unknown purchase state.")
            }
        } catch {
            return .failed(error.localizedDescription)
        }
    }

    private func observeTransactionUpdates() async {
        for await update in Transaction.updates {
            guard case .verified(let transaction) = update else { continue }
            if PremiumStoreProduct.allIDs.contains(transaction.productID) {
                await refreshEntitlements()
            }
            await transaction.finish()
        }
    }

    private static func isTransactionActive(_ transaction: Transaction) -> Bool {
        if transaction.revocationDate != nil { return false }
        if let expirationDate = transaction.expirationDate {
            return expirationDate > Date()
        }
        return true
    }
}

final class ViewController: NSViewController {
    private struct GoogleProfileDisplay {
        let name: String
        let email: String
        let pictureURL: URL?
    }

    private var palette = Palette(isDarkMode: true)
    private let typography = Typography()
    private let launchContentSize = NSSize(width: 920, height: 690)
    private let launchMinContentSize = NSSize(width: 760, height: 600)

    private var mainContentHost: NSView?
    /// Pin constraints for the current page inside `mainContentHost`; deactivated before each swap so relayout never stacks duplicates.
    private var mainContentHostPinConstraints: [NSLayoutConstraint] = []
    private var sidebarRowViews: [SidebarPage: NSView] = [:]
    private var selectedSidebarPage: SidebarPage = .joinMeetings
    private var selectedZoomJoinMode: ZoomJoinMode = .id
    private var pageCache: [SidebarPage: NSView] = [:]
    private var sidebarPageByView = [ObjectIdentifier: SidebarPage]()
    private var zoomJoinModeByView = [ObjectIdentifier: ZoomJoinMode]()
    private var zoomJoinModeViews: [ZoomJoinMode: NSView] = [:]
    private var settingsActionByView = [ObjectIdentifier: SettingsAction]()
    private var paywallWindow: NSWindow?
    private weak var paywallOverlayView: NSView?
    private let paywallContentWidth: CGFloat = 520
    private let launchWindowLeftOffset: CGFloat = 80
    private var selectedPremiumPlan: PremiumPlan = .monthly
    private var paywallPlanViews: [PremiumPlan: NSView] = [:]
    private var premiumPlanByView = [ObjectIdentifier: PremiumPlan]()
    private weak var paywallOfferLabel: NSTextField?
    private weak var paywallContinueLabel: NSTextField?
    private weak var paywallContinueButton: NSView?
    private weak var sidebarPremiumTitleLabel: NSTextField?
    private weak var sidebarPremiumIconView: NSImageView?
    private weak var sidebarPremiumButtonView: HoverTrackingView?
    private weak var instantMeetCardView: HoverSurfaceView?
    private weak var instantMeetTitleLabel: NSTextField?
    private weak var instantMeetSubtitleLabel: NSTextField?
    private weak var joinWithLinkCardView: HoverSurfaceView?
    private weak var joinWithLinkTitleLabel: NSTextField?
    private weak var joinMeetPrimaryButton: NSButton?
    private weak var meetLinkField: NSTextField?
    private weak var browseAddressField: NSTextField?
    private var inAppBrowserWindowController: InAppBrowserWindowController?
    private let googleOAuth = GoogleOAuthService.shared
    private let classroomClient = GoogleClassroomClient()
    private let storeKitCoordinator = StoreKitCoordinator()
    private var storeKitStartupTask: Task<Void, Never>?
    private var paywallPurchaseTask: Task<Void, Never>?
    private var paywallPriceLabels: [PremiumPlan: NSTextField] = [:]
    private var paywallSubtitleLabels: [PremiumPlan: NSTextField] = [:]
    private var paywallContinueEnabled = true
    private var paywallUpgradeFlowEnabled = false
    private let launchPaywallDelay: TimeInterval = 3
    private var hasCompletedInitialStoreKitSync = false
    private var hasPresentedLaunchPaywall = false
    private var launchPaywallWorkItem: DispatchWorkItem?
    private var hasViewAppearedOnce = false
    private var lastKnownPremiumAccess = false
    private var displayedScheduleTodos: [ClassroomTodoItem] = []
    private var enrolledCachedCourses: [ClassroomCourse] = []
    private var teachingCachedCourses: [ClassroomCourse] = []
    private var appUsageSessionStartDate: Date?
    private var hasObservedAppLifecycleForUsage = false
    private var premiumUpgradeRatingPromptWorkItem: DispatchWorkItem?

    private enum ScheduleFilter: Int {
        case all = 0
        case today = 1
        case week = 2
    }

    private enum SchedulePageFilter: Int {
        case all = 0
        case today = 1
        case week = 2
        case month = 3
        case customRange = 4
    }

    private var scheduleFilter: ScheduleFilter = .all
    private weak var scheduleDateHeadingLabel: NSTextField?
    private weak var scheduleCardsStack: NSStackView?
    private weak var scheduleCardsScrollView: NSScrollView?
    private weak var scheduleScrollLeftButton: NSView?
    private weak var scheduleScrollRightButton: NSView?
    private weak var scheduleFilterDropdown: NSPopUpButton?
    private weak var scheduleGoogleAuthButton: NSButton?
    private weak var scheduleGoogleAuthHostView: GoogleProfileAuthHostView?
    private var scheduleGoogleAuthHostPadWidthConstraint: NSLayoutConstraint?
    private var scheduleGoogleAuthHostPadHeightConstraint: NSLayoutConstraint?
    private var scheduleGoogleAuthButtonWidthConstraint: NSLayoutConstraint?
    private var scheduleGoogleAuthButtonHeightConstraint: NSLayoutConstraint?
    /// Circular avatar size when signed in (top-right, Google-style).
    private let scheduleGoogleSignedInAvatarSize: CGFloat = 36
    private var scheduleGoogleAuthHovering = false
    private var scheduleCurrentProfile: GoogleProfileDisplay?
    /// Larger copy of the header avatar for the account popover (optional).
    private var scheduleProfileMenuAvatar: NSImage?
    private var scheduleProfileImageTask: Task<Void, Never>?
    private var googleAccountPopover: NSPopover?
    private var scheduleCachedTodos: [ClassroomTodoItem] = []

    private var schedulePageFilter: SchedulePageFilter = .all
    private var schedulePageFromDate: Date = Calendar.current.startOfDay(for: Date())
    private var schedulePageToDate: Date = Calendar.current.startOfDay(for: Date())
    private var schedulePageFilteredTodos: [ClassroomTodoItem] = []
    private var schedulePageVisibleCount: Int = 0
    private let schedulePageBatchSize: Int = 6
    private let schedulePageCardsPerRow: Int = 3
    private let schedulePageCardSpacing: CGFloat = 20
    private let schedulePageCardHeight: CGFloat = 182
    /// Match `makeJoinMeetingsContent` vertical rhythm between sections.
    private let schedulePageStackSpacing: CGFloat = 14
    /// Tighter gap from header block (title + filters) to the date line below.
    private let schedulePageHeaderToDateSpacing: CGFloat = 10
    /// Join Meetings: gap from “Schedule” row to date heading, and date heading to card strip (keeps cards aligned with the rest of the column).
    private let joinPageScheduleHeaderToDateSpacing: CGFloat = 8
    private let joinPageDateToMeetingCardsSpacing: CGFloat = 8
    /// Match Join Meetings main content insets so the top auth/profile bar lines up with page edges.
    private let schedulePageLeadingInset: CGFloat = 28
    private let schedulePageTrailingInset: CGFloat = 28
    private var schedulePageScrollObservation: NSObjectProtocol?
    private weak var schedulePageDateHeadingLabel: NSTextField?
    private weak var schedulePageFilterDropdown: NSPopUpButton?
    private weak var schedulePageFromDatePicker: NSDatePicker?
    private weak var schedulePageToDatePicker: NSDatePicker?
    private weak var schedulePageRangeErrorLabel: NSTextField?
    private weak var schedulePageCardsStack: NSStackView?
    private weak var schedulePageCardsScrollView: NSScrollView?
    private weak var enrolledPageHeadingLabel: NSTextField?
    private weak var enrolledPageCardsStack: NSStackView?
    private weak var teachingPageHeadingLabel: NSTextField?
    private weak var teachingPageCardsStack: NSStackView?
    private var enrolledClassDetailsPopover: NSPopover?
    private var enrolledCourseByCardID: [String: ClassroomCourse] = [:]
    private var teachingCourseByCardID: [String: ClassroomCourse] = [:]

    private weak var topToastView: NSVisualEffectView?
    private var topToastHideWorkItem: DispatchWorkItem?

    /// In-app browser navigation: `.allowAll` or `.whitelist(hostSuffixes:)` (e.g. `["google.com"]` matches `meet.google.com`).
    private let inAppBrowserDefaultPolicy: InAppBrowserURLPolicy = .allowAll

    private let darkModeDefaultsKey = "settings.darkModeEnabled"
    private let appUsageAccumulatedSecondsDefaultsKey = "rating.appUsageAccumulatedSeconds"
    private let userHasRatedDefaultsKey = "rating.userHasRated"
    private let ratingStateMigrationV2DoneDefaultsKey = "rating.stateMigrationV2Done"
    private let ratingEligibleUsageSeconds: TimeInterval = 30 * 60
    private var darkModeEnabled: Bool {
        get {
            let hasValue = UserDefaults.standard.object(forKey: darkModeDefaultsKey) != nil
            return hasValue ? UserDefaults.standard.bool(forKey: darkModeDefaultsKey) : systemPrefersDarkMode()
        }
        set { UserDefaults.standard.set(newValue, forKey: darkModeDefaultsKey) }
    }

    private func makeSettingsPopover() -> NSPopover {
        let popover = NSPopover()
        popover.behavior = .transient
        popover.animates = true
        let showUpgradeInSettings = storeKitCoordinator.hasPremiumAccess && !storeKitCoordinator.hasLifetimeAccess
        let showRateUsInSettings = shouldShowRateUsInSettings
        popover.contentViewController = SettingsMenuViewController(
            palette: palette,
            typography: typography,
            darkModeEnabled: darkModeEnabled,
            showRateUsInSettings: showRateUsInSettings,
            showUpgradeInSettings: showUpgradeInSettings,
            onToggleDarkMode: { [weak self] enabled in
                self?.setDarkMode(enabled)
            },
            onAction: { [weak self] action, sourceView, clickPoint in
                self?.handleSettingsAction(action, sourceView: sourceView, clickLocationInSourceView: clickPoint)
            }
        )
        return popover
    }

    private var settingsPopover: NSPopover?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Sync toggle + palette with current macOS appearance on launch.
        darkModeEnabled = systemPrefersDarkMode()
        palette = Palette(isDarkMode: darkModeEnabled)
        storeKitCoordinator.onEntitlementsChanged = { [weak self] hasPremiumAccess in
            guard let self else { return }
            DispatchQueue.main.async {
                self.handlePremiumAccessChanged(hasPremiumAccess)
            }
        }
        migrateLegacyRatingStateIfNeeded()
        beginUsageTrackingSessionIfNeeded()
        observeAppLifecycleForUsageTrackingIfNeeded()
        setupRootView()
        buildMainLayout()
        startStoreKit()
    }

    override func viewDidAppear() {
        super.viewDidAppear()
        hasViewAppearedOnce = true
        presentLaunchPaywallIfNeeded()
        applyWindowTitle(for: selectedSidebarPage)
        guard let window = view.window else { return }

        configureUnifiedTitlebar(for: window)

        // Ensure launch size is applied even when macOS tries to restore prior window state.
        window.isRestorable = false
        window.setFrameAutosaveName("")

        DispatchQueue.main.async { [weak self, weak window] in
            guard let self, let window else { return }

            let frameSize = window.frameRect(forContentRect: NSRect(origin: .zero, size: self.launchContentSize)).size
            var newFrame = window.frame
            newFrame.size = frameSize
            window.setFrame(newFrame, display: true)
            window.center()
            if let screen = window.screen ?? NSScreen.main {
                var adjustedFrame = window.frame
                adjustedFrame.origin.x -= self.launchWindowLeftOffset
                let minX = screen.visibleFrame.minX
                adjustedFrame.origin.x = max(minX, adjustedFrame.origin.x)
                window.setFrame(adjustedFrame, display: true)
            }

            window.minSize = window.frameRect(forContentRect: NSRect(origin: .zero, size: self.launchMinContentSize)).size
        }
    }

    override var representedObject: Any? {
        didSet {}
    }

    deinit {
        premiumUpgradeRatingPromptWorkItem?.cancel()
        endUsageTrackingSession()
        if hasObservedAppLifecycleForUsage {
            NotificationCenter.default.removeObserver(self)
        }
        if let observer = schedulePageScrollObservation {
            NotificationCenter.default.removeObserver(observer)
        }
        storeKitStartupTask?.cancel()
        paywallPurchaseTask?.cancel()
        launchPaywallWorkItem?.cancel()
    }
}

private extension ViewController {
    func setupRootView() {
        view.appearance = NSAppearance(named: darkModeEnabled ? .darkAqua : .aqua)
        view.wantsLayer = true
        view.layer?.backgroundColor = palette.pageBackground.cgColor
    }

    func systemPrefersDarkMode() -> Bool {
        // Use the system-wide appearance setting (not app/window effective appearance).
        // When the key is missing, macOS is in Light mode.
        let global = UserDefaults.standard.persistentDomain(forName: UserDefaults.globalDomain)
        let style = global?["AppleInterfaceStyle"] as? String
        return style?.lowercased() == "dark"
    }

    func buildMainLayout() {
        let splitContainer = NSStackView()
        splitContainer.translatesAutoresizingMaskIntoConstraints = false
        splitContainer.orientation = .horizontal
        splitContainer.spacing = 14
        splitContainer.distribution = .fill
        splitContainer.alignment = .top
        view.addSubview(splitContainer)

        NSLayoutConstraint.activate([
            splitContainer.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            splitContainer.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            splitContainer.topAnchor.constraint(equalTo: view.topAnchor),
            splitContainer.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])

        let sidebar = makeSidebar()
        let mainPanel = makeMainPanel()
        sidebar.setContentHuggingPriority(.required, for: .horizontal)
        sidebar.setContentCompressionResistancePriority(.required, for: .horizontal)
        mainPanel.setContentHuggingPriority(.defaultLow, for: .horizontal)
        mainPanel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        splitContainer.addArrangedSubview(sidebar)
        splitContainer.addArrangedSubview(mainPanel)
    }

    @objc private func sidebarItemClicked(_ sender: NSClickGestureRecognizer) {
        guard let view = sender.view else { return }
        activateSidebarItem(view)
    }

    private func activateSidebarItem(_ view: NSView) {
        guard let page = sidebarPageByView[ObjectIdentifier(view)],
              page != selectedSidebarPage || page == .settings else { return }
        showSidebarPage(page)
    }

    @objc private func zoomJoinModeClicked(_ sender: NSClickGestureRecognizer) {
        guard let view = sender.view,
              let mode = zoomJoinModeByView[ObjectIdentifier(view)],
              mode != selectedZoomJoinMode else { return }
        selectedZoomJoinMode = mode
        updateZoomJoinModeAppearance()
        if selectedSidebarPage == .joinMeetings {
            pageCache[.joinMeetings] = nil
            showSidebarPage(.joinMeetings)
        }
    }

    @objc private func premiumButtonClicked(_ sender: NSClickGestureRecognizer) {
        if storeKitCoordinator.hasPremiumAccess {
            openManageSubscriptions()
        } else {
            showPaywall()
        }
    }

    @objc private func sidebarButtonClicked(_ sender: NSButton) {
        guard let page = SidebarPage(rawValue: sender.tag),
              page != selectedSidebarPage || page == .settings else { return }
        showSidebarPage(page)
    }

    @objc private func joinMeetClicked(_ sender: Any?) {
        let rawInput = meetLinkField?.stringValue.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""

        guard let url = normalizedClassroomURL(from: rawInput) else {
            showSimpleAlert(
                title: "Invalid Classroom link",
                message: "Enter a valid Google Classroom link or class code (for example classroom.google.com, classroom.google.com/c/your-class-id, or paste a class code)."
            )
            return
        }

        openURL(url)
    }

    @objc private func joinWithLinkCardClicked(_ sender: NSClickGestureRecognizer) {
        meetLinkField?.window?.makeFirstResponder(meetLinkField)
    }

    @objc private func cancelMeetJoinClicked(_ sender: Any?) {
        meetLinkField?.stringValue = ""
    }

    @objc private func browseOpenAddressClicked(_ sender: Any?) {
        let raw = browseAddressField?.stringValue.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        guard raw.isEmpty == false else {
            showSimpleAlert(title: "Browse", message: "Enter a web address (for example classroom.google.com).")
            return
        }
        let normalized = normalizedURLString(from: raw)
        guard let url = URL(string: normalized), url.scheme == "http" || url.scheme == "https" else {
            showSimpleAlert(title: "Invalid address", message: "Enter a valid http or https URL.")
            return
        }
        openURL(url)
    }

    @objc private func browseQuickLinkMeetClicked(_ sender: Any?) {
        guard let url = URL(string: "https://classroom.google.com/") else { return }
        openURL(url)
    }

    @objc private func browseQuickLinkMeetHelpClicked(_ sender: Any?) {
        guard let url = URL(string: "https://support.google.com/classroom") else { return }
        openURL(url)
    }

    @objc private func browseQuickLinkZoomHelpClicked(_ sender: Any?) {
        guard let url = URL(string: "https://support.zoom.us") else { return }
        openURL(url)
    }

    @objc private func instantMeetClicked(_ sender: NSClickGestureRecognizer) {
        guard let url = URL(string: "https://classroom.google.com/") else { return }
        openURL(url)
    }

    private func normalizedURLString(from value: String) -> String {
        if value.lowercased().hasPrefix("http://") || value.lowercased().hasPrefix("https://") {
            return value
        }
        return "https://\(value)"
    }

    /// Bare class IDs used in `/c/...` paths: alphanumeric, typical Classroom length range.
    private func isValidClassroomClassCode(_ code: String) -> Bool {
        let trimmed = code.trimmingCharacters(in: .whitespacesAndNewlines)
        guard trimmed.isEmpty == false else { return false }
        guard (6...64).contains(trimmed.count) else { return false }
        let allowed = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-_"))
        return trimmed.unicodeScalars.allSatisfy { allowed.contains($0) }
    }

    /// Accepts `https://classroom.google.com/...`, host-only, or a bare class code for `/c/...`.
    private func normalizedClassroomURL(from rawInput: String) -> URL? {
        let trimmed = rawInput.trimmingCharacters(in: .whitespacesAndNewlines)
        guard trimmed.isEmpty == false else { return nil }

        let lower = trimmed.lowercased()

        func classroomHost(_ host: String) -> Bool {
            host == "classroom.google.com" || host.hasSuffix(".classroom.google.com")
        }

        if lower.hasPrefix("http://") || lower.hasPrefix("https://") {
            guard let url = URL(string: trimmed), let host = url.host?.lowercased(), classroomHost(host) else {
                return nil
            }
            var components = URLComponents(url: url, resolvingAgainstBaseURL: false)
            components?.scheme = "https"
            components?.host = host
            return components?.url
        }

        if lower == "classroom.google.com" || lower == "www.classroom.google.com" {
            return URL(string: "https://classroom.google.com/")
        }

        if lower.hasPrefix("classroom.google.com/") || lower.hasPrefix("www.classroom.google.com/") {
            let hostLen = lower.hasPrefix("www.") ? "www.classroom.google.com".count : "classroom.google.com".count
            let rest = String(trimmed.dropFirst(hostLen))
            let path = rest.hasPrefix("/") ? rest : "/" + rest
            return URL(string: "https://classroom.google.com\(path)")
        }

        let code = trimmed.replacingOccurrences(of: " ", with: "")
        if isValidClassroomClassCode(code) {
            return URL(string: "https://classroom.google.com/c/\(code)")
        }

        return nil
    }

    private func openInAppBrowser(with url: URL, policy: InAppBrowserURLPolicy = .allowAll) {
        let browserController: InAppBrowserWindowController
        if let existing = inAppBrowserWindowController {
            browserController = existing
        } else {
            browserController = InAppBrowserWindowController()
            inAppBrowserWindowController = browserController
        }

        browserController.load(url: url, policy: policy)
        browserController.applyDefaultFrameCenteredOnVisibleScreen()
        browserController.showWindow(nil)
        browserController.window?.makeKeyAndOrderFront(nil)
        browserController.window?.orderFrontRegardless()
        NSApp.activate(ignoringOtherApps: true)
    }

    private func openInDefaultBrowser(url: URL) {
        NSWorkspace.shared.open(url, configuration: NSWorkspace.OpenConfiguration()) { [weak self] _, error in
            if let error {
                DispatchQueue.main.async {
                    self?.showSimpleAlert(title: "Unable to open browser", message: error.localizedDescription)
                }
            }
        }
    }

    private func openURLWithRouting(_ url: URL, policy: InAppBrowserURLPolicy = .allowAll) {
        let scheme = (url.scheme ?? "").lowercased()
        if scheme == "http" || scheme == "https" {
            openInAppBrowser(with: url, policy: policy)
            return
        }
        openInDefaultBrowser(url: url)
    }

    private func openRateUsDestination() {
        let configured = (Bundle.main.object(forInfoDictionaryKey: "RateUsURL") as? String)?
            .trimmingCharacters(in: .whitespacesAndNewlines)
        let placeholder = (Bundle.main.object(forInfoDictionaryKey: "AppLaunchPlaceholderURL") as? String)?
            .trimmingCharacters(in: .whitespacesAndNewlines)
        let hardcodedRateUsURL = "https://apps.apple.com/mac/search?term=Google%20Classroom"

        var candidateStrings = [String]()
        if let configured, !configured.isEmpty {
            candidateStrings.append(configured)
            if let appID = extractAppleAppID(from: configured) {
                candidateStrings.append("macappstore://apps.apple.com/app/id\(appID)")
                candidateStrings.append("macappstore://itunes.apple.com/app/id\(appID)")
            }
        }
        candidateStrings.append(hardcodedRateUsURL)
        if let placeholder, !placeholder.isEmpty {
            candidateStrings.append(placeholder)
        }

        for candidate in candidateStrings {
            guard let url = URL(string: candidate) else { continue }
            if NSWorkspace.shared.open(url) {
                return
            }
        }

        showSimpleAlert(
            title: "Unable to Open Rate Page",
            message: "Could not open the App Store rating page. Please try again."
        )

        requestAppRatingIfEligible(markAsRated: true)
    }

    private func extractAppleAppID(from urlString: String) -> String? {
        guard let match = urlString.range(of: "id[0-9]+", options: .regularExpression) else {
            return nil
        }
        let token = String(urlString[match])
        return String(token.dropFirst())
    }

    private func openInSafari(url: URL) {
        guard let safariAppURL = NSWorkspace.shared.urlForApplication(withBundleIdentifier: "com.apple.Safari") else {
            NSWorkspace.shared.open(url)
            return
        }

        let configuration = NSWorkspace.OpenConfiguration()
        NSWorkspace.shared.open([url], withApplicationAt: safariAppURL, configuration: configuration) { _, error in
            if let error {
                self.showSimpleAlert(title: "Unable to Open Safari", message: error.localizedDescription)
            }
        }
    }

    private func openManageSubscriptions() {
        // Do not use `openURL` — it routes http(s) links through the in-app browser (`openURLWithRouting`).
        // StoreKit's `AppStore.showManageSubscriptions` is iOS-only (UIWindowScene). On macOS, open the Mac App Store via `macappstore://` or the account URL in the user's default browser.
        if let appStoreURL = URL(string: "macappstore://apps.apple.com/account/subscriptions"),
           NSWorkspace.shared.open(appStoreURL) {
            return
        }
        guard let httpsURL = URL(string: "https://apps.apple.com/account/subscriptions") else {
            showSimpleAlert(title: "Unable to Open Subscriptions", message: "The subscriptions URL is invalid.")
            return
        }
        NSWorkspace.shared.open(httpsURL)
    }

    private func shareAppURL() -> URL? {
        if let configured = Bundle.main.object(forInfoDictionaryKey: "AppShareURL") as? String {
            let trimmed = configured.trimmingCharacters(in: .whitespacesAndNewlines)
            if trimmed.isEmpty == false, let url = URL(string: trimmed) {
                return url
            }
        }
        return nil
    }

    private func shareAppFromSettingsMenu(sourceView: NSView? = nil, clickLocationInSourceView: NSPoint? = nil) {
        let appName = Bundle.main.object(forInfoDictionaryKey: "CFBundleDisplayName") as? String
            ?? Bundle.main.object(forInfoDictionaryKey: "CFBundleName") as? String
            ?? "Google Classroom App"
        let message = "Check out \(appName) for Google Classroom and your classwork."
        let appURL = shareAppURL()
        let shareItems: [Any] = appURL.map { [message, $0] } ?? [message]

        let picker = NSSharingServicePicker(items: shareItems)
        let anchorView = sourceView ?? sidebarRowViews[.settings] ?? view
        let anchorPoint = clickLocationInSourceView
            ?? NSPoint(x: anchorView.bounds.midX, y: anchorView.bounds.midY)
        let anchorRect = NSRect(x: anchorPoint.x, y: anchorPoint.y, width: 1, height: 1)
        picker.show(relativeTo: anchorRect, of: anchorView, preferredEdge: .minY)

        let clipboardText = ([message, appURL?.absoluteString].compactMap { $0 }).joined(separator: "\n")
        NSPasteboard.general.clearContents()
        NSPasteboard.general.setString(clipboardText, forType: .string)
    }

    private func showSidebarPage(_ page: SidebarPage) {
        selectedSidebarPage = page
        updateSidebarAppearance()
        applyWindowTitle(for: page)

        guard let host = mainContentHost else { return }
        NSLayoutConstraint.deactivate(mainContentHostPinConstraints)
        mainContentHostPinConstraints.removeAll()
        host.subviews.forEach { $0.removeFromSuperview() }
        let child = viewForPage(page)
        child.translatesAutoresizingMaskIntoConstraints = false
        host.addSubview(child)
        mainContentHostPinConstraints = [
            child.leadingAnchor.constraint(equalTo: host.leadingAnchor),
            child.trailingAnchor.constraint(equalTo: host.trailingAnchor),
            child.topAnchor.constraint(equalTo: host.topAnchor),
            child.bottomAnchor.constraint(equalTo: host.bottomAnchor)
        ]
        NSLayoutConstraint.activate(mainContentHostPinConstraints)
    }

    private func showSettingsPopover() {
        guard let anchor = sidebarRowViews[.settings] else { return }
        if settingsPopover?.isShown == true {
            settingsPopover?.performClose(nil)
            return
        }

        settingsPopover = makeSettingsPopover()
        if let menu = settingsPopover?.contentViewController as? SettingsMenuViewController {
            menu.setDarkModeEnabled(darkModeEnabled)
        }

        settingsPopover?.show(relativeTo: anchor.bounds, of: anchor, preferredEdge: .maxX)
    }

    private func setDarkMode(_ enabled: Bool) {
        darkModeEnabled = enabled
        NSApp.appearance = NSAppearance(named: enabled ? .darkAqua : .aqua)
        view.appearance = NSAppearance(named: enabled ? .darkAqua : .aqua)
        palette = Palette(isDarkMode: enabled)
        reloadTheme()
    }

    private func reloadTheme() {
        pageCache.removeAll()
        if let observer = schedulePageScrollObservation {
            NotificationCenter.default.removeObserver(observer)
        }
        schedulePageScrollObservation = nil
        sidebarRowViews.removeAll()
        sidebarPageByView.removeAll()
        zoomJoinModeByView.removeAll()
        zoomJoinModeViews.removeAll()
        settingsActionByView.removeAll()
        paywallPlanViews.removeAll()
        premiumPlanByView.removeAll()
        paywallPriceLabels.removeAll()
        paywallSubtitleLabels.removeAll()
        paywallContinueLabel = nil
        paywallContinueButton = nil
        paywallContinueEnabled = true

        googleAccountPopover?.performClose(nil)
        googleAccountPopover = nil

        NSLayoutConstraint.deactivate(mainContentHostPinConstraints)
        mainContentHostPinConstraints.removeAll()
        mainContentHost = nil
        view.subviews.forEach { $0.removeFromSuperview() }
        setupRootView()
        buildMainLayout()
        showSidebarPage(selectedSidebarPage)
    }

    private func handleSettingsAction(_ action: SettingsAction, sourceView: NSView? = nil, clickLocationInSourceView: NSPoint? = nil) {
        switch action {
        case .restore:
            Task { [weak self] in
                guard let self else { return }
                let message = await self.storeKitCoordinator.restorePurchases()
                self.refreshPaywallStoreUI()
                self.showSimpleAlert(title: "Restore Purchases", message: message)
            }
        case .rateUs:
            openRateUsDestination()
        case .support:
            openSettingsLink(infoKey: "SupportURL")
        case .privacyPolicy:
            openSettingsLink(infoKey: "PrivacyPolicyURL")
        case .termsOfServices:
            openSettingsLink(infoKey: "TermsOfServiceURL")
        case .moreApps:
            if let moreAppsURL = Bundle.main.object(forInfoDictionaryKey: "MoreAppsURL") as? String,
               let url = URL(string: moreAppsURL) {
                openURL(url)
            }
        case .shareApp:
            shareAppFromSettingsMenu(sourceView: sourceView, clickLocationInSourceView: clickLocationInSourceView)
        case .upgrade:
            showPaywall(upgradeFlow: true, preferredPlan: .lifetime)
        }
    }

    private func openSettingsLink(infoKey: String) {
        let defaultURL = (Bundle.main.object(forInfoDictionaryKey: "AppLaunchPlaceholderURL") as? String) ?? "https://example.com/app-link-coming-soon"
        let urlString = (Bundle.main.object(forInfoDictionaryKey: infoKey) as? String) ?? defaultURL
        guard let url = URL(string: urlString) else { return }
        openURL(url)
    }

    private func showSimpleAlert(title: String, message: String) {
        let alert = NSAlert()
        alert.messageText = title
        alert.informativeText = message
        alert.addButton(withTitle: "OK")
        alert.runModal()
    }

    private func showTopToast(message: String, isError: Bool) {
        topToastHideWorkItem?.cancel()
        topToastHideWorkItem = nil
        topToastView?.removeFromSuperview()
        topToastView = nil

        let toast = NSVisualEffectView()
        toast.translatesAutoresizingMaskIntoConstraints = false
        toast.material = darkModeEnabled ? .hudWindow : .popover
        toast.blendingMode = .withinWindow
        toast.state = .active
        toast.wantsLayer = true
        toast.layer?.cornerRadius = 10
        toast.layer?.masksToBounds = true
        toast.layer?.borderWidth = 1
        toast.layer?.borderColor = NSColor.white.withAlphaComponent(darkModeEnabled ? 0.10 : 0.18).cgColor
        toast.layer?.backgroundColor = NSColor.black.withAlphaComponent(darkModeEnabled ? 0.68 : 0.78).cgColor
        toast.alphaValue = 0

        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.alignment = .centerY
        row.spacing = 8
        row.distribution = .fill

        let icon = NSImageView()
        icon.translatesAutoresizingMaskIntoConstraints = false
        icon.imageScaling = .scaleProportionallyDown
        icon.image = NSImage(
            systemSymbolName: isError ? "xmark.circle.fill" : "checkmark.circle.fill",
            accessibilityDescription: isError ? "Error" : "Success"
        )
        icon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 16, weight: .semibold)
        icon.contentTintColor = isError ? NSColor.systemRed : NSColor.systemGreen

        let label = textLabel(
            message,
            font: NSFont.systemFont(ofSize: 13, weight: .semibold),
            color: NSColor.white
        )
        label.alignment = .left
        label.maximumNumberOfLines = 2
        label.lineBreakMode = .byWordWrapping
        row.addArrangedSubview(icon)
        row.addArrangedSubview(label)
        toast.addSubview(row)

        view.addSubview(toast)
        NSLayoutConstraint.activate([
            toast.topAnchor.constraint(equalTo: view.topAnchor, constant: 14),
            toast.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            toast.widthAnchor.constraint(lessThanOrEqualTo: view.widthAnchor, constant: -40),
            toast.heightAnchor.constraint(greaterThanOrEqualToConstant: 40),

            icon.widthAnchor.constraint(equalToConstant: 16),
            icon.heightAnchor.constraint(equalToConstant: 16),

            row.leadingAnchor.constraint(equalTo: toast.leadingAnchor, constant: 14),
            row.trailingAnchor.constraint(equalTo: toast.trailingAnchor, constant: -14),
            row.topAnchor.constraint(equalTo: toast.topAnchor, constant: 10),
            row.bottomAnchor.constraint(equalTo: toast.bottomAnchor, constant: -10)
        ])

        topToastView = toast

        NSAnimationContext.runAnimationGroup { context in
            context.duration = 0.18
            context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
            toast.animator().alphaValue = 1
        }

        let hideWorkItem = DispatchWorkItem { [weak self, weak toast] in
            guard let self, let toast else { return }
            NSAnimationContext.runAnimationGroup({ context in
                context.duration = 0.2
                context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
                toast.animator().alphaValue = 0
            }, completionHandler: {
                toast.removeFromSuperview()
                if self.topToastView === toast {
                    self.topToastView = nil
                }
            })
        }
        topToastHideWorkItem = hideWorkItem
        DispatchQueue.main.asyncAfter(deadline: .now() + 2.0, execute: hideWorkItem)
    }

    private func confirmPremiumUpgrade() -> Bool {
        let alert = NSAlert()
        alert.messageText = "Already Premium"
        alert.informativeText = "You are already premium. Do you want to continue with this purchase?"
        alert.addButton(withTitle: "Continue")
        alert.addButton(withTitle: "Cancel")
        return alert.runModal() == .alertFirstButtonReturn
    }

    private func showPaywall(upgradeFlow: Bool = false, preferredPlan: PremiumPlan? = nil) {
        if !Thread.isMainThread {
            DispatchQueue.main.async { [weak self] in
                self?.showPaywall(upgradeFlow: upgradeFlow, preferredPlan: preferredPlan)
            }
            return
        }
        paywallUpgradeFlowEnabled = upgradeFlow
        if let preferredPlan {
            selectedPremiumPlan = preferredPlan
        }
        if let existingOverlay = paywallOverlayView {
            refreshPaywallStoreUI()
            existingOverlay.alphaValue = 1
            view.addSubview(existingOverlay, positioned: .above, relativeTo: nil)
            return
        }
        if let existing = paywallWindow {
            refreshPaywallStoreUI()
            animatePaywallPresentation(existing)
            existing.makeKeyAndOrderFront(nil)
            NSApp.activate(ignoringOtherApps: true)
            return
        }

        let content = makePaywallContent()
        let overlay = NSView()
        overlay.translatesAutoresizingMaskIntoConstraints = false
        overlay.wantsLayer = true
        overlay.layer?.backgroundColor = palette.pageBackground.withAlphaComponent(0.98).cgColor
        overlay.alphaValue = 0
        overlay.addSubview(content)
        view.addSubview(overlay, positioned: .above, relativeTo: nil)
        NSLayoutConstraint.activate([
            overlay.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            overlay.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            overlay.topAnchor.constraint(equalTo: view.topAnchor),
            overlay.bottomAnchor.constraint(equalTo: view.bottomAnchor),

            content.leadingAnchor.constraint(equalTo: overlay.leadingAnchor),
            content.trailingAnchor.constraint(equalTo: overlay.trailingAnchor),
            content.topAnchor.constraint(equalTo: overlay.topAnchor),
            content.bottomAnchor.constraint(equalTo: overlay.bottomAnchor)
        ])
        paywallOverlayView = overlay
        NSAnimationContext.runAnimationGroup { context in
            context.duration = 0.20
            context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
            overlay.animator().alphaValue = 1
        }

        Task { [weak self] in
            guard let self else { return }
            await self.storeKitCoordinator.refreshProducts()
            self.refreshPaywallStoreUI()
        }
    }

    private func animatePaywallPresentation(_ window: NSWindow) {
        let finalFrame = window.frame
        let targetScreen = window.screen ?? NSScreen.main
        let startY: CGFloat
        if let screen = targetScreen {
            startY = screen.visibleFrame.maxY + 12
        } else {
            startY = finalFrame.origin.y + 120
        }
        let startFrame = NSRect(x: finalFrame.origin.x, y: startY, width: finalFrame.width, height: finalFrame.height)

        window.setFrame(startFrame, display: false)
        window.alphaValue = 0

        NSAnimationContext.runAnimationGroup { context in
            context.duration = 0.28
            context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
            window.animator().alphaValue = 1
            window.animator().setFrame(finalFrame, display: true)
        }
    }

    @objc private func closePaywallClicked(_ sender: Any?) {
        if let overlay = paywallOverlayView {
            paywallOverlayView = nil
            paywallUpgradeFlowEnabled = false
            NSAnimationContext.runAnimationGroup({ context in
                context.duration = 0.16
                context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
                overlay.animator().alphaValue = 0
            }, completionHandler: {
                overlay.removeFromSuperview()
            })
            return
        }
        if let win = paywallWindow {
            win.performClose(nil)
            return
        }
    }

    @objc private func paywallFooterLinkClicked(_ sender: NSClickGestureRecognizer) {
        guard let view = sender.view else { return }
        let text = (view.subviews.first { $0 is NSTextField } as? NSTextField)?.stringValue ?? "Link"
        let defaultURL = (Bundle.main.object(forInfoDictionaryKey: "AppLaunchPlaceholderURL") as? String) ?? "https://example.com/app-link-coming-soon"
        let map: [String: String] = [
            "Privacy Policy": (Bundle.main.object(forInfoDictionaryKey: "PrivacyPolicyURL") as? String) ?? defaultURL,
            "Support": (Bundle.main.object(forInfoDictionaryKey: "SupportURL") as? String) ?? defaultURL,
            "Terms of Services": (Bundle.main.object(forInfoDictionaryKey: "TermsOfServiceURL") as? String) ?? defaultURL
        ]
        if let urlString = map[text], let url = URL(string: urlString) {
            openURL(url)
            return
        }
        showSimpleAlert(title: text, message: "\(text) tapped.")
    }

    @objc private func paywallPlanClicked(_ sender: NSClickGestureRecognizer) {
        guard let view = sender.view,
              let plan = premiumPlanByView[ObjectIdentifier(view)] else { return }
        selectedPremiumPlan = plan
        updatePaywallPlanSelection()
    }

    @objc private func paywallPlanButtonClicked(_ sender: NSButton) {
        guard let plan = PremiumPlan(rawValue: sender.tag) else { return }
        selectedPremiumPlan = plan
        updatePaywallPlanSelection()
    }

    private func updatePaywallPlanSelection() {
        for (plan, view) in paywallPlanViews {
            applyPaywallPlanStyle(view, isSelected: plan == selectedPremiumPlan)
        }
        paywallOfferLabel?.stringValue = paywallOfferText(for: selectedPremiumPlan)
    }

    private func paywallOfferText(for plan: PremiumPlan) -> String {
        if storeKitCoordinator.hasPremiumAccess {
            if storeKitCoordinator.hasLifetimeAccess {
                return "Lifetime premium is active on this Apple ID."
            }
            if paywallUpgradeFlowEnabled {
                let currentPlanName = storeKitCoordinator.activeNonLifetimePlan?.displayName ?? "Premium"
                if plan == .lifetime {
                    return "Current plan: \(currentPlanName). Tap Continue to upgrade to Lifetime."
                }
                return "Current plan: \(currentPlanName). Select Lifetime to upgrade."
            }
            return "Premium is active on this Apple ID."
        }
        let productID = PremiumStoreProduct.productID(for: plan)
        if let product = storeKitCoordinator.productsByID[productID] {
            let pkrPrice = pkrDisplayPrice(product.displayPrice)
            if product.type == .nonConsumable {
                return "\(pkrPrice) one-time purchase"
            }
            if let period = product.subscription?.subscriptionPeriod {
                return "\(pkrPrice)/\(subscriptionUnitText(period.unit))"
            }
            return pkrPrice
        }
        switch plan {
        case .weekly:
            return "PKR 1,100.00/week"
        case .monthly:
            return "Free for 3 Days then PKR 2,500.00/month"
        case .yearly:
            return "PKR 9,900.00/year (about 190.38/week)"
        case .lifetime:
            return "PKR 14,900.00 one-time purchase"
        }
    }

    private func pkrDisplayPrice(_ value: String) -> String {
        if value.hasPrefix("PKR ") { return value }
        if value.hasPrefix("Rs ") {
            return "PKR " + value.dropFirst(3)
        }
        if value.contains("PKR") { return value }
        return "PKR \(value)"
    }

    private func subscriptionUnitText(_ unit: Product.SubscriptionPeriod.Unit) -> String {
        switch unit {
        case .day: return "day"
        case .week: return "week"
        case .month: return "month"
        case .year: return "year"
        @unknown default: return "period"
        }
    }

    private func startStoreKit() {
        storeKitStartupTask?.cancel()
        storeKitStartupTask = Task { [weak self] in
            guard let self else { return }
            await self.storeKitCoordinator.start()
            self.hasCompletedInitialStoreKitSync = true
            self.refreshPaywallStoreUI()
            self.presentLaunchPaywallIfNeeded()
        }
    }

    private func refreshPaywallStoreUI() {
        for (plan, label) in paywallPriceLabels {
            let productID = PremiumStoreProduct.productID(for: plan)
            if let product = storeKitCoordinator.productsByID[productID] {
                label.stringValue = pkrDisplayPrice(product.displayPrice)
            }
        }
        for (plan, label) in paywallSubtitleLabels {
            let productID = PremiumStoreProduct.productID(for: plan)
            guard let product = storeKitCoordinator.productsByID[productID],
                  let period = product.subscription?.subscriptionPeriod else { continue }
            label.stringValue = "\(pkrDisplayPrice(product.displayPrice))/\(subscriptionUnitText(period.unit))"
        }
        refreshSidebarPremiumButton()
        refreshInstantMeetPremiumState()
        updatePaywallPlanSelection()
        updatePaywallContinueState(isLoading: false)
    }

    private func refreshInstantMeetPremiumState() {
        instantMeetCardView?.alphaValue = 1.0
        instantMeetTitleLabel?.alphaValue = 1.0
        instantMeetSubtitleLabel?.alphaValue = 1.0
        instantMeetCardView?.toolTip = nil
        instantMeetCardView?.onHoverChanged?(false)

        joinWithLinkCardView?.alphaValue = 1.0
        joinWithLinkTitleLabel?.alphaValue = 1.0
        meetLinkField?.isEditable = true
        meetLinkField?.isSelectable = true
        meetLinkField?.alphaValue = 1.0
        joinMeetPrimaryButton?.isEnabled = true
        joinMeetPrimaryButton?.alphaValue = 1.0
        joinWithLinkCardView?.toolTip = nil
    }

    private func handlePremiumAccessChanged(_ hasPremiumAccess: Bool) {
        let hadPremiumAccess = lastKnownPremiumAccess
        lastKnownPremiumAccess = hasPremiumAccess
        premiumUpgradeRatingPromptWorkItem?.cancel()
        refreshPaywallStoreUI()
        refreshScheduleCardsForPremiumStateChange()
        refreshPagesAfterPremiumStateUpdate()
        Task { [weak self] in
            await self?.loadSchedule()
        }

        if !hadPremiumAccess && hasPremiumAccess {
            if selectedSidebarPage != .joinMeetings {
                Task { [weak self] in
                    await self?.loadSchedule()
                }
            }
            // Skip delayed review prompt during initial launch entitlement sync.
            // We only want this after a real in-session upgrade.
            if hasCompletedInitialStoreKitSync {
                scheduleRatingPromptAfterPremiumUpgrade()
            }
        }
        if hadPremiumAccess && !hasPremiumAccess {
            showPaywall()
        }
    }

    private func refreshPagesAfterPremiumStateUpdate() {
        pageCache[.joinMeetings] = nil
        pageCache[.photo] = nil
        pageCache[.enrolled] = nil
        pageCache[.teaching] = nil
        pageCache[.settings] = nil
        showSidebarPage(selectedSidebarPage)
    }

    private var userHasRated: Bool {
        UserDefaults.standard.bool(forKey: userHasRatedDefaultsKey)
    }

    private var accumulatedAppUsageSeconds: TimeInterval {
        get {
            UserDefaults.standard.double(forKey: appUsageAccumulatedSecondsDefaultsKey)
        }
        set {
            UserDefaults.standard.set(newValue, forKey: appUsageAccumulatedSecondsDefaultsKey)
        }
    }

    private var totalTrackedUsageSeconds: TimeInterval {
        let liveSessionSeconds: TimeInterval
        if let start = appUsageSessionStartDate {
            liveSessionSeconds = max(0, Date().timeIntervalSince(start))
        } else {
            liveSessionSeconds = 0
        }
        return accumulatedAppUsageSeconds + liveSessionSeconds
    }

    private var hasReachedRatingUsageThreshold: Bool {
        totalTrackedUsageSeconds >= ratingEligibleUsageSeconds
    }

    private var shouldShowRateUsInSettings: Bool {
        true
    }

    private func migrateLegacyRatingStateIfNeeded() {
        let defaults = UserDefaults.standard
        guard !defaults.bool(forKey: ratingStateMigrationV2DoneDefaultsKey) else { return }
        // Legacy behavior marked "rated" immediately after requesting review.
        // Clear once so testing and new logic can run correctly.
        defaults.set(false, forKey: userHasRatedDefaultsKey)
        defaults.set(true, forKey: ratingStateMigrationV2DoneDefaultsKey)
    }

    private func beginUsageTrackingSessionIfNeeded() {
        guard appUsageSessionStartDate == nil else { return }
        appUsageSessionStartDate = Date()
    }

    private func endUsageTrackingSession() {
        guard let start = appUsageSessionStartDate else { return }
        let sessionElapsedSeconds = max(0, Date().timeIntervalSince(start))
        accumulatedAppUsageSeconds += sessionElapsedSeconds
        appUsageSessionStartDate = nil
    }

    private func observeAppLifecycleForUsageTrackingIfNeeded() {
        guard !hasObservedAppLifecycleForUsage else { return }
        hasObservedAppLifecycleForUsage = true
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(applicationDidBecomeActiveForUsageTracking),
            name: NSApplication.didBecomeActiveNotification,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(applicationWillResignActiveForUsageTracking),
            name: NSApplication.willResignActiveNotification,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(applicationWillTerminateForUsageTracking),
            name: NSApplication.willTerminateNotification,
            object: nil
        )
    }

    @objc private func applicationDidBecomeActiveForUsageTracking() {
        beginUsageTrackingSessionIfNeeded()
    }

    @objc private func applicationWillResignActiveForUsageTracking() {
        endUsageTrackingSession()
    }

    @objc private func applicationWillTerminateForUsageTracking() {
        endUsageTrackingSession()
    }

    private func scheduleRatingPromptAfterPremiumUpgrade() {
        guard !userHasRated else { return }
        let workItem = DispatchWorkItem { [weak self] in
            self?.requestAppRatingIfEligible(markAsRated: false)
        }
        premiumUpgradeRatingPromptWorkItem = workItem
        DispatchQueue.main.asyncAfter(deadline: .now() + 10, execute: workItem)
    }

    private func requestAppRatingIfEligible(markAsRated: Bool) {
        guard storeKitCoordinator.hasPremiumAccess, !userHasRated else { return }
        SKStoreReviewController.requestReview()
        if markAsRated {
            UserDefaults.standard.set(true, forKey: userHasRatedDefaultsKey)
        }
    }

    private func refreshScheduleCardsForPremiumStateChange() {
        if let stack = scheduleCardsStack {
            renderScheduleCards(into: stack, todos: displayedScheduleTodos)
        }
        applySchedulePageFiltersAndRender()
    }

    private func refreshSidebarPremiumButton() {
        let isPremium = storeKitCoordinator.hasPremiumAccess
        if isPremium {
            sidebarPremiumTitleLabel?.stringValue = "Manage Subscription"
            sidebarPremiumIconView?.image = premiumButtonSymbolImage(named: "crown.fill")
        } else {
            sidebarPremiumTitleLabel?.stringValue = "Get Premium"
            sidebarPremiumIconView?.image = premiumButtonSymbolImage(named: "star.fill")
        }
        sidebarPremiumIconView?.contentTintColor = .white
        sidebarPremiumButtonView?.onHoverChanged?(false)
    }

    private func premiumButtonSymbolImage(named symbolName: String) -> NSImage? {
        let configuration = NSImage.SymbolConfiguration(pointSize: 12, weight: .semibold)
        return NSImage(systemSymbolName: symbolName, accessibilityDescription: nil)?
            .withSymbolConfiguration(configuration)
    }

    private func presentLaunchPaywallIfNeeded() {
        guard hasCompletedInitialStoreKitSync, hasViewAppearedOnce, !hasPresentedLaunchPaywall else { return }
        hasPresentedLaunchPaywall = true
        if !storeKitCoordinator.hasPremiumAccess {
            launchPaywallWorkItem?.cancel()
            let workItem = DispatchWorkItem { [weak self] in
                guard let self else { return }
                self.launchPaywallWorkItem = nil
                guard !self.storeKitCoordinator.hasPremiumAccess else { return }
                self.showPaywall()
            }
            launchPaywallWorkItem = workItem
            DispatchQueue.main.asyncAfter(deadline: .now() + launchPaywallDelay, execute: workItem)
        }
    }

    @objc private func paywallContinueClicked(_ sender: Any?) {
        startSelectedPlanPurchase()
    }

    private func startSelectedPlanPurchase() {
        guard paywallContinueEnabled else {
            if storeKitCoordinator.hasPremiumAccess {
                showSimpleAlert(title: "Premium Active", message: "This Apple ID already has premium access.")
            } else {
                showSimpleAlert(title: "Please Wait", message: "A purchase is already being processed.")
            }
            return
        }
        if paywallUpgradeFlowEnabled && storeKitCoordinator.hasPremiumAccess && !confirmPremiumUpgrade() {
            return
        }
        paywallPurchaseTask?.cancel()
        updatePaywallContinueState(isLoading: true)
        let selectedPlan = selectedPremiumPlan
        paywallPurchaseTask = Task { [weak self] in
            guard let self else { return }
            let result = await self.storeKitCoordinator.purchase(plan: selectedPlan)
            self.updatePaywallContinueState(isLoading: false)
            self.refreshPaywallStoreUI()
            switch result {
            case .success:
                self.refreshPagesAfterPremiumStateUpdate()
                Task { [weak self] in
                    await self?.loadSchedule()
                }
                self.showSimpleAlert(title: "Purchase Complete", message: "Premium has been unlocked successfully.")
                self.closePaywallClicked(nil)
                self.scheduleRatingPromptAfterPremiumUpgrade()
            case .cancelled:
                break
            case .pending:
                self.showSimpleAlert(title: "Purchase Pending", message: "Your purchase is pending approval. You can continue once it completes.")
            case .unavailable:
                self.showSimpleAlert(title: "Product Not Available", message: "Unable to load this product. Check your StoreKit configuration and product IDs.")
            case .alreadyOwned:
                self.showSimpleAlert(title: "Already Purchased", message: "This plan is already active on your Apple ID.")
            case .failed(let message):
                self.showSimpleAlert(title: "Purchase Failed", message: message)
            }
        }
    }

    private func updatePaywallContinueState(isLoading: Bool) {
        if isLoading {
            paywallContinueEnabled = false
            paywallContinueLabel?.stringValue = "Processing..."
            paywallContinueButton?.alphaValue = 0.75
            return
        }
        if storeKitCoordinator.hasLifetimeAccess {
            paywallContinueEnabled = false
            paywallContinueLabel?.stringValue = "Premium Active"
            paywallContinueButton?.alphaValue = 0.75
        } else if paywallUpgradeFlowEnabled && storeKitCoordinator.hasPremiumAccess {
            paywallContinueEnabled = true
            paywallContinueLabel?.stringValue = "Continue"
            paywallContinueButton?.alphaValue = 1.0
        } else {
            paywallContinueEnabled = true
            paywallContinueLabel?.stringValue = "Continue"
            paywallContinueButton?.alphaValue = 1.0
        }
    }

    private func applyPaywallPlanStyle(_ card: NSView, isSelected: Bool, hovering: Bool = false) {
        let selectedBorder = NSColor(calibratedRed: 1.0, green: 0.60, blue: 0.20, alpha: 1)
        let idleBorder = palette.inputBorder
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverIdleBackground =
            palette.sectionCard.blended(withFraction: 0.10, of: hoverBlend) ?? palette.sectionCard
        let selectedBackground = darkModeEnabled
            ? NSColor(calibratedRed: 30.0 / 255.0, green: 34.0 / 255.0, blue: 42.0 / 255.0, alpha: 1)
            : NSColor(calibratedRed: 255.0 / 255.0, green: 246.0 / 255.0, blue: 236.0 / 255.0, alpha: 1)
        card.layer?.backgroundColor = (isSelected ? selectedBackground : (hovering ? hoverIdleBackground : palette.sectionCard)).cgColor
        card.layer?.borderColor = (isSelected ? selectedBorder : (hovering ? selectedBorder.withAlphaComponent(0.55) : idleBorder)).cgColor
        card.layer?.borderWidth = isSelected ? 2 : 1
        card.layer?.shadowColor = NSColor.black.cgColor
        card.layer?.shadowOpacity = isSelected ? (darkModeEnabled ? 0.26 : 0.10) : (hovering ? 0.18 : 0.12)
        card.layer?.shadowOffset = CGSize(width: 0, height: -1)
        card.layer?.shadowRadius = isSelected ? (darkModeEnabled ? 10 : 6) : (hovering ? 7 : 5)
    }

    private func viewForPage(_ page: SidebarPage) -> NSView {
        if let cached = pageCache[page] { return cached }
        let built: NSView
        switch page {
        case .joinMeetings:
            built = makeJoinMeetingsContent()
        case .photo:
            built = makeSchedulePageContent()
        case .enrolled:
            built = makeEnrolledPageContent()
        case .teaching:
            built = makeTeachingPageContent()
        case .settings:
            built = makeSettingsPageContent()
        }
        pageCache[page] = built
        return built
    }

    private func makePlaceholderPage(title: String, subtitle: String) -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        let titleLabel = textLabel(title, font: typography.pageTitle, color: palette.textPrimary)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        let sub = textLabel(subtitle, font: typography.fieldLabel, color: palette.textSecondary)
        sub.translatesAutoresizingMaskIntoConstraints = false
        panel.addSubview(titleLabel)
        panel.addSubview(sub)
        NSLayoutConstraint.activate([
            titleLabel.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 28),
            titleLabel.topAnchor.constraint(equalTo: panel.topAnchor),
            sub.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            sub.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 8)
        ])
        return panel
    }

    private func makeSettingsPageContent() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false

        let scroll = NSScrollView()
        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.drawsBackground = false
        scroll.hasHorizontalScroller = false
        scroll.hasVerticalScroller = true
        scroll.autohidesScrollers = true
        scroll.borderType = .noBorder
        scroll.scrollerStyle = .overlay
        scroll.automaticallyAdjustsContentInsets = false
        let clip = TopAlignedClipView()
        clip.drawsBackground = false
        scroll.contentView = clip
        panel.addSubview(scroll)

        let content = NSView()
        content.translatesAutoresizingMaskIntoConstraints = false
        scroll.documentView = content

        let card = roundedContainer(cornerRadius: 16, color: palette.sectionCard)
        card.translatesAutoresizingMaskIntoConstraints = false
        styleSurface(card, borderColor: palette.inputBorder, borderWidth: 1, shadow: true)
        content.addSubview(card)

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.orientation = .vertical
        stack.spacing = 18
        stack.alignment = .leading
        card.addSubview(stack)

        let pageTitle = textLabel("Settings", font: typography.pageTitle, color: palette.textPrimary)
        let pageSubtitle = textLabel("Manage appearance, account, and app options.", font: typography.fieldLabel, color: palette.textSecondary)
        stack.addArrangedSubview(pageTitle)
        stack.addArrangedSubview(pageSubtitle)
        stack.setCustomSpacing(24, after: pageSubtitle)

        let appearanceTitle = textLabel("Appearance", font: typography.joinWithURLTitle, color: palette.textPrimary)
        stack.addArrangedSubview(appearanceTitle)
        let darkModeRow = makeSettingsDarkModeRow()
        stack.addArrangedSubview(darkModeRow)
        darkModeRow.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        stack.setCustomSpacing(24, after: darkModeRow)

        let accountTitle = textLabel("Account", font: typography.joinWithURLTitle, color: palette.textPrimary)
        stack.addArrangedSubview(accountTitle)
        let googleAccountRow = makeSettingsGoogleAccountRow()
        stack.addArrangedSubview(googleAccountRow)
        googleAccountRow.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        stack.setCustomSpacing(24, after: googleAccountRow)

        let appTitle = textLabel("App", font: typography.joinWithURLTitle, color: palette.textPrimary)
        stack.addArrangedSubview(appTitle)

        if shouldShowRateUsInSettings {
            let rateButton = makeSettingsActionButton(icon: "★", title: "Rate Us", action: .rateUs)
            stack.addArrangedSubview(rateButton)
            rateButton.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        }
        let shareButton = makeSettingsActionButton(icon: "⤴︎", title: "Share App", action: .shareApp)
        stack.addArrangedSubview(shareButton)
        shareButton.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        if storeKitCoordinator.hasPremiumAccess && !storeKitCoordinator.hasLifetimeAccess {
            let upgradeButton = makeSettingsActionButton(icon: "⬆︎", title: "Upgrade", action: .upgrade)
            stack.addArrangedSubview(upgradeButton)
            upgradeButton.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            stack.setCustomSpacing(24, after: upgradeButton)
        } else {
            stack.setCustomSpacing(24, after: shareButton)
        }

        let legalTitle = textLabel("Help & Legal", font: typography.joinWithURLTitle, color: palette.textPrimary)
        stack.addArrangedSubview(legalTitle)
        let privacyButton = makeSettingsActionButton(icon: "🔒", title: "Privacy Policy", action: .privacyPolicy)
        stack.addArrangedSubview(privacyButton)
        privacyButton.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        let supportButton = makeSettingsActionButton(icon: "💬", title: "Support", action: .support)
        stack.addArrangedSubview(supportButton)
        supportButton.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        let termsButton = makeSettingsActionButton(icon: "📄", title: "Terms of Services", action: .termsOfServices)
        stack.addArrangedSubview(termsButton)
        termsButton.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        NSLayoutConstraint.activate([
            scroll.leadingAnchor.constraint(equalTo: panel.leadingAnchor),
            scroll.trailingAnchor.constraint(equalTo: panel.trailingAnchor),
            scroll.topAnchor.constraint(equalTo: panel.topAnchor),
            scroll.bottomAnchor.constraint(equalTo: panel.bottomAnchor),

            content.leadingAnchor.constraint(equalTo: scroll.contentView.leadingAnchor),
            content.trailingAnchor.constraint(equalTo: scroll.contentView.trailingAnchor),
            content.topAnchor.constraint(equalTo: scroll.contentView.topAnchor),
            content.bottomAnchor.constraint(greaterThanOrEqualTo: scroll.contentView.bottomAnchor),
            content.widthAnchor.constraint(equalTo: scroll.contentView.widthAnchor),

            card.centerXAnchor.constraint(equalTo: content.centerXAnchor),
            card.topAnchor.constraint(equalTo: content.topAnchor, constant: 36),
            content.bottomAnchor.constraint(greaterThanOrEqualTo: card.bottomAnchor, constant: 36),
            card.widthAnchor.constraint(lessThanOrEqualToConstant: 620),
            card.widthAnchor.constraint(greaterThanOrEqualToConstant: 460),
            card.leadingAnchor.constraint(greaterThanOrEqualTo: content.leadingAnchor, constant: 30),
            card.trailingAnchor.constraint(lessThanOrEqualTo: content.trailingAnchor, constant: -30),

            stack.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 28),
            stack.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -28),
            stack.topAnchor.constraint(equalTo: card.topAnchor, constant: 24),
            stack.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -24)
        ])

        return panel
    }

    private func makeSettingsDarkModeRow() -> NSView {
        let row = roundedContainer(cornerRadius: 10, color: palette.inputBackground)
        row.translatesAutoresizingMaskIntoConstraints = false
        row.heightAnchor.constraint(equalToConstant: 52).isActive = true
        styleSurface(row, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let icon = textLabel("◐", font: NSFont.systemFont(ofSize: 18, weight: .medium), color: palette.textPrimary)
        let title = textLabel("Dark Mode", font: NSFont.systemFont(ofSize: 15, weight: .semibold), color: palette.textPrimary)
        let toggle = NSSwitch()
        toggle.translatesAutoresizingMaskIntoConstraints = false
        toggle.state = darkModeEnabled ? .on : .off
        toggle.target = self
        toggle.action = #selector(settingsPageDarkModeToggled(_:))

        row.addSubview(icon)
        row.addSubview(title)
        row.addSubview(toggle)
        NSLayoutConstraint.activate([
            icon.leadingAnchor.constraint(equalTo: row.leadingAnchor, constant: 14),
            icon.centerYAnchor.constraint(equalTo: row.centerYAnchor),
            title.leadingAnchor.constraint(equalTo: icon.trailingAnchor, constant: 10),
            title.centerYAnchor.constraint(equalTo: row.centerYAnchor),
            toggle.trailingAnchor.constraint(equalTo: row.trailingAnchor, constant: -14),
            toggle.centerYAnchor.constraint(equalTo: row.centerYAnchor)
        ])
        return row
    }

    private func makeSettingsGoogleAccountRow() -> NSView {
        let row = roundedContainer(cornerRadius: 10, color: palette.inputBackground)
        row.translatesAutoresizingMaskIntoConstraints = false
        styleSurface(row, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let signedIn = googleOAuth.loadTokens() != nil
        let titleText = signedIn ? (scheduleCurrentProfile?.name ?? "Google account connected") : "Google account not connected"
        let subtitleText = signedIn ? (scheduleCurrentProfile?.email ?? "Signed in") : "Sign in to sync your Google account with classwork and to-do."

        let title = textLabel(titleText, font: NSFont.systemFont(ofSize: 15, weight: .semibold), color: palette.textPrimary)
        let subtitle = textLabel(subtitleText, font: NSFont.systemFont(ofSize: 13, weight: .regular), color: palette.textSecondary)
        subtitle.maximumNumberOfLines = 2
        subtitle.lineBreakMode = .byTruncatingTail

        let actionButton = NSButton(title: signedIn ? "Sign Out" : "Sign in with Google", target: self, action: #selector(settingsGoogleActionButtonClicked(_:)))
        actionButton.translatesAutoresizingMaskIntoConstraints = false
        actionButton.bezelStyle = .rounded
        actionButton.controlSize = .regular

        row.addSubview(title)
        row.addSubview(subtitle)
        row.addSubview(actionButton)
        NSLayoutConstraint.activate([
            row.heightAnchor.constraint(equalToConstant: 78),
            title.leadingAnchor.constraint(equalTo: row.leadingAnchor, constant: 14),
            title.topAnchor.constraint(equalTo: row.topAnchor, constant: 12),
            subtitle.leadingAnchor.constraint(equalTo: title.leadingAnchor),
            subtitle.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 4),
            subtitle.trailingAnchor.constraint(lessThanOrEqualTo: actionButton.leadingAnchor, constant: -14),
            actionButton.trailingAnchor.constraint(equalTo: row.trailingAnchor, constant: -14),
            actionButton.centerYAnchor.constraint(equalTo: row.centerYAnchor)
        ])

        return row
    }

    private func makeSettingsActionButton(icon: String, title: String, action: SettingsAction) -> NSButton {
        let button = HoverButton(title: "", target: self, action: #selector(settingsPageActionButtonClicked(_:)))
        button.translatesAutoresizingMaskIntoConstraints = false
        button.isBordered = false
        button.wantsLayer = true
        button.layer?.cornerRadius = 10
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        styleSurface(button, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)
        button.heightAnchor.constraint(equalToConstant: 46).isActive = true
        button.tag = action.rawValue

        let iconLabel = textLabel(icon, font: NSFont.systemFont(ofSize: 17, weight: .medium), color: palette.textPrimary)
        let titleLabel = textLabel(title, font: NSFont.systemFont(ofSize: 15, weight: .semibold), color: palette.textPrimary)
        button.addSubview(iconLabel)
        button.addSubview(titleLabel)
        NSLayoutConstraint.activate([
            iconLabel.leadingAnchor.constraint(equalTo: button.leadingAnchor, constant: 14),
            iconLabel.centerYAnchor.constraint(equalTo: button.centerYAnchor),
            titleLabel.leadingAnchor.constraint(equalTo: iconLabel.trailingAnchor, constant: 10),
            titleLabel.centerYAnchor.constraint(equalTo: button.centerYAnchor)
        ])
        return button
    }

    @objc private func settingsPageDarkModeToggled(_ sender: NSSwitch) {
        setDarkMode(sender.state == .on)
    }

    @objc private func settingsPageActionButtonClicked(_ sender: NSButton) {
        guard let action = SettingsAction(rawValue: sender.tag) else { return }
        let clickPoint: NSPoint?
        if let event = NSApp.currentEvent {
            let pointInWindow = event.locationInWindow
            clickPoint = sender.convert(pointInWindow, from: nil)
        } else {
            clickPoint = nil
        }
        handleSettingsAction(action, sourceView: sender, clickLocationInSourceView: clickPoint)
    }

    @objc private func settingsGoogleActionButtonClicked(_ sender: NSButton) {
        if googleOAuth.loadTokens() == nil {
            scheduleConnectClicked()
        } else {
            performGoogleSignOut()
        }
    }

    func makeBrowseWebContent() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false

        let titleLabel = textLabel("Browse the web", font: typography.pageTitle, color: palette.textPrimary)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        let sub = textLabel(
            "Open sites in the in-app browser (back, forward, reload, address bar). OAuth and “Continue in browser” flows stay inside the app.",
            font: typography.fieldLabel,
            color: palette.textSecondary
        )
        sub.translatesAutoresizingMaskIntoConstraints = false
        sub.maximumNumberOfLines = 0
        sub.lineBreakMode = .byWordWrapping

        let fieldShell = roundedContainer(cornerRadius: 8, color: palette.inputBackground)
        fieldShell.translatesAutoresizingMaskIntoConstraints = false
        fieldShell.heightAnchor.constraint(equalToConstant: 44).isActive = true
        styleSurface(fieldShell, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let field = NSTextField(string: "")
        field.translatesAutoresizingMaskIntoConstraints = false
        field.isEditable = true
        field.isBordered = false
        field.drawsBackground = false
        field.focusRingType = .none
        field.font = NSFont.systemFont(ofSize: 14, weight: .regular)
        field.textColor = palette.textPrimary
        field.placeholderString = "https://example.com or example.com"
        field.delegate = self
        browseAddressField = field
        fieldShell.addSubview(field)

        let openBtn = meetActionButton(
            title: "Open in app browser",
            color: palette.primaryBlue,
            textColor: .white,
            width: 220,
            action: #selector(browseOpenAddressClicked(_:))
        )

        let quickTitle = textLabel("Quick links", font: typography.joinWithURLTitle, color: palette.textPrimary)
        quickTitle.translatesAutoresizingMaskIntoConstraints = false

        let quickRow = NSStackView()
        quickRow.translatesAutoresizingMaskIntoConstraints = false
        quickRow.orientation = .horizontal
        quickRow.spacing = 10
        quickRow.addArrangedSubview(browseQuickLinkButton(title: "Google Classroom", action: #selector(browseQuickLinkMeetClicked(_:))))
        quickRow.addArrangedSubview(browseQuickLinkButton(title: "Classroom help", action: #selector(browseQuickLinkMeetHelpClicked(_:))))
        quickRow.addArrangedSubview(browseQuickLinkButton(title: "Zoom help", action: #selector(browseQuickLinkZoomHelpClicked(_:))))

        panel.addSubview(titleLabel)
        panel.addSubview(sub)
        panel.addSubview(fieldShell)
        panel.addSubview(openBtn)
        panel.addSubview(quickTitle)
        panel.addSubview(quickRow)

        NSLayoutConstraint.activate([
            titleLabel.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 28),
            titleLabel.topAnchor.constraint(equalTo: panel.topAnchor, constant: 26),
            titleLabel.trailingAnchor.constraint(lessThanOrEqualTo: panel.trailingAnchor, constant: -28),

            sub.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            sub.trailingAnchor.constraint(lessThanOrEqualTo: panel.trailingAnchor, constant: -28),
            sub.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 10),

            fieldShell.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            fieldShell.trailingAnchor.constraint(equalTo: panel.trailingAnchor, constant: -28),
            fieldShell.topAnchor.constraint(equalTo: sub.bottomAnchor, constant: 18),

            field.leadingAnchor.constraint(equalTo: fieldShell.leadingAnchor, constant: 12),
            field.trailingAnchor.constraint(equalTo: fieldShell.trailingAnchor, constant: -12),
            field.centerYAnchor.constraint(equalTo: fieldShell.centerYAnchor),

            openBtn.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            openBtn.topAnchor.constraint(equalTo: fieldShell.bottomAnchor, constant: 12),
            openBtn.heightAnchor.constraint(equalToConstant: 36),

            quickTitle.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            quickTitle.topAnchor.constraint(equalTo: openBtn.bottomAnchor, constant: 28),

            quickRow.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            quickRow.topAnchor.constraint(equalTo: quickTitle.bottomAnchor, constant: 10)
        ])

        return panel
    }

    private func browseQuickLinkButton(title: String, action: Selector) -> NSButton {
        let b = NSButton(title: title, target: self, action: action)
        b.translatesAutoresizingMaskIntoConstraints = false
        b.bezelStyle = .rounded
        b.font = NSFont.systemFont(ofSize: 13, weight: .medium)
        return b
    }

    private func configureUnifiedTitlebar(for window: NSWindow) {
        window.styleMask.insert(.fullSizeContentView)
        window.titlebarAppearsTransparent = true
        window.titleVisibility = .hidden
    }

    private func applyWindowTitle(for page: SidebarPage) {
        let title: String
        switch page {
        case .joinMeetings:
            title = "App for Google Classroom"
        case .photo:
            title = "To-Do"
        case .enrolled:
            title = "Enrolled"
        case .teaching:
            title = "Teaching"
        case .settings:
            title = "Settings"
        }
        view.window?.title = title
    }

    private func updateSidebarAppearance() {
        for (page, row) in sidebarRowViews {
            applySidebarRowStyle(row, page: page, logoTemplate: logoTemplateForSidebarPage(page))
        }
    }

    private func logoTemplateForSidebarPage(_ page: SidebarPage) -> Bool {
        switch page {
        case .photo: return false
        case .joinMeetings, .enrolled, .teaching, .settings: return true
        }
    }

    func makeSidebar() -> NSView {
        let sidebar = NSView()
        sidebar.translatesAutoresizingMaskIntoConstraints = false
        sidebar.wantsLayer = true
        sidebar.layer?.backgroundColor = palette.sidebarBackground.cgColor
        sidebar.layer?.borderColor = palette.separator.cgColor
        sidebar.layer?.borderWidth = 1
        sidebar.layer?.shadowColor = NSColor.black.cgColor
        sidebar.layer?.shadowOpacity = 0.18
        sidebar.layer?.shadowOffset = CGSize(width: 2, height: 0)
        sidebar.layer?.shadowRadius = 10
        sidebar.widthAnchor.constraint(equalToConstant: 224).isActive = true

        let appIconView = NSImageView()
        if let classroomLogo = NSImage(named: "icon_google_classroom") {
            classroomLogo.isTemplate = false
            appIconView.image = classroomLogo
        } else if let headerLogo = NSImage(named: "HeaderLogo") {
            headerLogo.isTemplate = false
            appIconView.image = headerLogo
        } else if let appIconImage = NSApplication.shared.applicationIconImage {
            appIconImage.isTemplate = false
            appIconView.image = appIconImage
        }
        appIconView.translatesAutoresizingMaskIntoConstraints = false
        appIconView.imageScaling = NSImageScaling.scaleProportionallyDown
        appIconView.imageAlignment = NSImageAlignment.alignCenter
        appIconView.contentTintColor = nil
        appIconView.widthAnchor.constraint(equalToConstant: 40).isActive = true
        appIconView.heightAnchor.constraint(equalToConstant: 40).isActive = true

        let sidebarBrandLabel = textLabel("Classroom", font: NSFont.systemFont(ofSize: 24, weight: .bold), color: palette.textPrimary)
        sidebarBrandLabel.maximumNumberOfLines = 1
        sidebarBrandLabel.lineBreakMode = .byTruncatingTail
        sidebarBrandLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
        sidebarBrandLabel.setContentHuggingPriority(.defaultLow, for: .horizontal)

        let titleRow = NSStackView(views: [
            appIconView,
            sidebarBrandLabel
        ])
        titleRow.translatesAutoresizingMaskIntoConstraints = false
        titleRow.orientation = NSUserInterfaceLayoutOrientation.horizontal
        titleRow.alignment = NSLayoutConstraint.Attribute.centerY
        titleRow.spacing = 12

        let menuStack = NSStackView()
        menuStack.translatesAutoresizingMaskIntoConstraints = false
        menuStack.orientation = .vertical
        menuStack.alignment = .leading
        menuStack.spacing = 10

        menuStack.addArrangedSubview(sidebarSectionTitle("Classes"))
        let joinRow = sidebarItem("Open Classroom", icon: "􀉣", page: .joinMeetings, logoImageName: "JoinMeetingsLogo", logoIconWidth: 24, logoHeightMultiplier: 56.0 / 52.0)
        menuStack.addArrangedSubview(joinRow)
        sidebarRowViews[.joinMeetings] = joinRow
        menuStack.addArrangedSubview(sidebarSectionTitle("Planning"))
        let photoRow = sidebarItem("To-Do", icon: "􀏂", page: .photo, systemSymbolName: "clock.badge.checkmark")
        menuStack.addArrangedSubview(photoRow)
        sidebarRowViews[.photo] = photoRow
        let enrolledRow = sidebarItem("Enrolled", icon: "􀆄", page: .enrolled, systemSymbolName: "person.3.sequence.fill")
        menuStack.addArrangedSubview(enrolledRow)
        sidebarRowViews[.enrolled] = enrolledRow
        let teachingRow = sidebarItem("Teaching", icon: "􀅼", page: .teaching, systemSymbolName: "person.2.badge.gearshape.fill")
        menuStack.addArrangedSubview(teachingRow)
        sidebarRowViews[.teaching] = teachingRow
        menuStack.addArrangedSubview(sidebarSectionTitle("Additional"))
        let settingsRow = sidebarItem("Settings", icon: "􀍟", page: .settings, logoImageName: "SidebarSettingsLogo", logoIconWidth: 28, logoHeightMultiplier: 68.0 / 62.0, showsDisclosure: true)
        menuStack.addArrangedSubview(settingsRow)
        sidebarRowViews[.settings] = settingsRow

        let premiumButton = sidebarPremiumButton()

        sidebar.addSubview(titleRow)
        sidebar.addSubview(menuStack)
        sidebar.addSubview(premiumButton)

        NSLayoutConstraint.activate([
            titleRow.leadingAnchor.constraint(equalTo: sidebar.leadingAnchor, constant: 16),
            titleRow.topAnchor.constraint(equalTo: sidebar.safeAreaLayoutGuide.topAnchor, constant: 24),
            titleRow.trailingAnchor.constraint(lessThanOrEqualTo: sidebar.trailingAnchor, constant: -16),

            menuStack.leadingAnchor.constraint(equalTo: sidebar.leadingAnchor, constant: 12),
            menuStack.trailingAnchor.constraint(equalTo: sidebar.trailingAnchor, constant: -12),
            menuStack.topAnchor.constraint(equalTo: titleRow.bottomAnchor, constant: 20),
            menuStack.bottomAnchor.constraint(lessThanOrEqualTo: premiumButton.topAnchor, constant: -16),

            premiumButton.leadingAnchor.constraint(equalTo: sidebar.leadingAnchor, constant: 12),
            premiumButton.trailingAnchor.constraint(equalTo: sidebar.trailingAnchor, constant: -12),
            premiumButton.bottomAnchor.constraint(equalTo: sidebar.bottomAnchor, constant: -14)
        ])

        for subview in menuStack.arrangedSubviews {
            subview.widthAnchor.constraint(equalTo: menuStack.widthAnchor).isActive = true
        }

        return sidebar
    }

    func sidebarPremiumButton() -> NSView {
        let button = HoverTrackingView()
        button.translatesAutoresizingMaskIntoConstraints = false
        button.wantsLayer = true
        button.layer?.cornerRadius = 17
        button.layer?.backgroundColor = palette.primaryBlue.cgColor
        button.heightAnchor.constraint(equalToConstant: 34).isActive = true
        styleSurface(button, borderColor: palette.primaryBlueBorder, borderWidth: 1, shadow: false)

        let icon = NSImageView()
        icon.translatesAutoresizingMaskIntoConstraints = false
        icon.imageScaling = .scaleProportionallyUpOrDown
        icon.contentTintColor = .white
        icon.image = premiumButtonSymbolImage(named: "star.fill")
        let title = textLabel("Get Premium", font: NSFont.systemFont(ofSize: 14, weight: .semibold), color: .white)
        button.addSubview(icon)
        button.addSubview(title)

        NSLayoutConstraint.activate([
            icon.leadingAnchor.constraint(equalTo: button.leadingAnchor, constant: 12),
            icon.centerYAnchor.constraint(equalTo: button.centerYAnchor),
            icon.widthAnchor.constraint(equalToConstant: 14),
            icon.heightAnchor.constraint(equalToConstant: 14),
            title.leadingAnchor.constraint(equalTo: icon.trailingAnchor, constant: 8),
            title.centerYAnchor.constraint(equalTo: button.centerYAnchor),
            title.trailingAnchor.constraint(lessThanOrEqualTo: button.trailingAnchor, constant: -12)
        ])

        button.onHoverChanged = { [weak self, weak button] hovering in
            guard let self, let button else { return }
            let isPremium = self.storeKitCoordinator.hasPremiumAccess
            let baseColor = isPremium
                ? NSColor(calibratedRed: 0.93, green: 0.73, blue: 0.16, alpha: 1.0)
                : self.palette.primaryBlue
            let borderColor = isPremium
                ? NSColor(calibratedRed: 0.78, green: 0.56, blue: 0.10, alpha: 1.0)
                : self.palette.primaryBlueBorder
            let hoverColor: NSColor
            let hoverBorderColor: NSColor
            if isPremium {
                // Darker rich-gold hover for stronger premium feedback.
                hoverColor = NSColor(calibratedRed: 0.84, green: 0.62, blue: 0.11, alpha: 1.0)
                hoverBorderColor = NSColor(calibratedRed: 0.67, green: 0.46, blue: 0.07, alpha: 1.0)
            } else {
                let hoverBlend = self.darkModeEnabled ? NSColor.white : NSColor.black
                hoverColor = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
                hoverBorderColor = borderColor
            }
            button.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            button.layer?.shadowColor = NSColor.black.cgColor
            button.layer?.shadowOpacity = hovering ? (isPremium ? 0.30 : 0.20) : 0.14
            button.layer?.shadowOffset = CGSize(width: 0, height: -1)
            button.layer?.shadowRadius = hovering ? (isPremium ? 8 : 6) : 4
            self.styleSurface(button, borderColor: (hovering ? hoverBorderColor : borderColor), borderWidth: hovering ? 1.5 : 1, shadow: false)
        }
        button.onHoverChanged?(false)
        sidebarPremiumTitleLabel = title
        sidebarPremiumIconView = icon
        sidebarPremiumButtonView = button
        refreshSidebarPremiumButton()

        let click = NSClickGestureRecognizer(target: self, action: #selector(premiumButtonClicked(_:)))
        button.addGestureRecognizer(click)
        return button
    }

    func makeMainPanel() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        panel.wantsLayer = true
        panel.layer?.backgroundColor = palette.pageBackground.cgColor

        let authBar = scheduleTopAuthRow()
        authBar.translatesAutoresizingMaskIntoConstraints = false
        panel.addSubview(authBar)

        let host = NSView()
        host.translatesAutoresizingMaskIntoConstraints = false
        panel.addSubview(host)
        NSLayoutConstraint.activate([
            authBar.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 28),
            authBar.trailingAnchor.constraint(equalTo: panel.trailingAnchor, constant: -28),
            authBar.topAnchor.constraint(equalTo: panel.safeAreaLayoutGuide.topAnchor, constant: 26),

            host.leadingAnchor.constraint(equalTo: panel.leadingAnchor),
            host.trailingAnchor.constraint(equalTo: panel.trailingAnchor),
            host.topAnchor.constraint(equalTo: authBar.bottomAnchor, constant: 20),
            host.bottomAnchor.constraint(equalTo: panel.bottomAnchor)
        ])
        mainContentHost = host

        if googleOAuth.loadTokens() != nil, let profile = scheduleCurrentProfile {
            applyGoogleProfile(profile)
        }

        // Preserve the currently selected page during rebuilds (e.g. dark mode toggle).
        showSidebarPage(selectedSidebarPage)

        return panel
    }

    func makeJoinMeetingsContent() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false

        let contentStack = NSStackView()
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        contentStack.orientation = .vertical
        contentStack.spacing = 14
        contentStack.alignment = .leading

        let joinActions = meetJoinActionsRow()
        contentStack.addArrangedSubview(textLabel("Google Classroom", font: typography.pageTitle, color: palette.textPrimary))
        contentStack.addArrangedSubview(meetJoinSectionRow())
        contentStack.addArrangedSubview(joinActions)
        contentStack.setCustomSpacing(26, after: joinActions)
        let scheduleHeaderView = scheduleHeader()
        contentStack.addArrangedSubview(scheduleHeaderView)
        contentStack.setCustomSpacing(joinPageScheduleHeaderToDateSpacing, after: scheduleHeaderView)

        let dateHeading = textLabel(scheduleInitialHeadingText(), font: typography.dateHeading, color: palette.textSecondary)
        scheduleDateHeadingLabel = dateHeading
        contentStack.addArrangedSubview(dateHeading)
        contentStack.setCustomSpacing(joinPageDateToMeetingCardsSpacing, after: dateHeading)

        let cardsRow = scheduleCardsRow(todos: [])
        contentStack.addArrangedSubview(cardsRow)

        panel.addSubview(contentStack)

        NSLayoutConstraint.activate([
            contentStack.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 28),
            contentStack.trailingAnchor.constraint(equalTo: panel.trailingAnchor, constant: -28),
            contentStack.topAnchor.constraint(equalTo: panel.topAnchor)
        ])

        Task { [weak self] in
            await self?.loadSchedule()
        }

        return panel
    }

    func makeSchedulePageContent() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        panel.userInterfaceLayoutDirection = .leftToRight

        let contentStack = NSStackView()
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        contentStack.userInterfaceLayoutDirection = .leftToRight
        contentStack.orientation = .vertical
        contentStack.spacing = schedulePageStackSpacing
        contentStack.alignment = .width
        contentStack.distribution = .fill

        let header = schedulePageHeader()
        header.setContentHuggingPriority(.required, for: .vertical)
        header.setContentCompressionResistancePriority(.required, for: .vertical)
        contentStack.addArrangedSubview(header)
        contentStack.setCustomSpacing(schedulePageHeaderToDateSpacing, after: header)

        let heading = textLabel(schedulePageInitialHeadingText(), font: typography.dateHeading, color: palette.textSecondary)
        heading.alignment = .left
        heading.setContentHuggingPriority(.required, for: .vertical)
        heading.setContentCompressionResistancePriority(.required, for: .vertical)
        schedulePageDateHeadingLabel = heading
        contentStack.addArrangedSubview(heading)

        let rangeError = textLabel("", font: NSFont.systemFont(ofSize: 12, weight: .semibold), color: .systemRed)
        rangeError.alignment = .left
        rangeError.isHidden = true
        rangeError.setContentHuggingPriority(.required, for: .vertical)
        rangeError.setContentCompressionResistancePriority(.required, for: .vertical)
        schedulePageRangeErrorLabel = rangeError
        contentStack.addArrangedSubview(rangeError)

        let cardsContainer = makeSchedulePageCardsContainer()
        cardsContainer.setContentHuggingPriority(.defaultLow, for: .vertical)
        contentStack.addArrangedSubview(cardsContainer)

        panel.addSubview(contentStack)

        NSLayoutConstraint.activate([
            contentStack.leftAnchor.constraint(equalTo: panel.leftAnchor, constant: schedulePageLeadingInset),
            contentStack.rightAnchor.constraint(equalTo: panel.rightAnchor, constant: -schedulePageTrailingInset),
            contentStack.topAnchor.constraint(equalTo: panel.topAnchor),
            contentStack.bottomAnchor.constraint(equalTo: panel.bottomAnchor, constant: -16),
            header.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            heading.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            rangeError.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            cardsContainer.widthAnchor.constraint(equalTo: contentStack.widthAnchor)
        ])

        Task { [weak self] in
            await self?.loadSchedule()
        }

        return panel
    }

    func makeEnrolledPageContent() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        panel.userInterfaceLayoutDirection = .leftToRight

        let contentStack = NSStackView()
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        contentStack.userInterfaceLayoutDirection = .leftToRight
        contentStack.orientation = .vertical
        contentStack.spacing = 14
        contentStack.alignment = .width
        contentStack.distribution = .fill

        let titleRow = NSStackView()
        titleRow.translatesAutoresizingMaskIntoConstraints = false
        titleRow.userInterfaceLayoutDirection = .leftToRight
        titleRow.orientation = .horizontal
        titleRow.alignment = .centerY
        titleRow.distribution = .fill
        titleRow.spacing = 10

        let titleLabel = textLabel("Enrolled Classes", font: typography.pageTitle, color: palette.textPrimary)
        titleLabel.alignment = .left
        titleLabel.maximumNumberOfLines = 1
        titleLabel.lineBreakMode = .byTruncatingTail
        titleLabel.setContentHuggingPriority(.required, for: .horizontal)
        titleLabel.setContentCompressionResistancePriority(.required, for: .horizontal)

        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false
        spacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
        spacer.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        let refreshButton = makeScheduleRefreshButton()
        refreshButton.target = self
        refreshButton.action = #selector(enrolledPageRefreshPressed(_:))

        titleRow.addArrangedSubview(titleLabel)
        titleRow.addArrangedSubview(spacer)
        titleRow.addArrangedSubview(refreshButton)

        let heading = textLabel(enrolledPageInitialHeadingText(), font: typography.dateHeading, color: palette.textSecondary)
        heading.alignment = .left
        heading.maximumNumberOfLines = 2
        heading.lineBreakMode = .byWordWrapping
        enrolledPageHeadingLabel = heading

        let scroll = NSScrollView()
        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.userInterfaceLayoutDirection = .leftToRight
        scroll.drawsBackground = false
        scroll.hasHorizontalScroller = false
        scroll.hasVerticalScroller = true
        scroll.autohidesScrollers = true
        scroll.borderType = .noBorder
        scroll.scrollerStyle = .overlay
        scroll.automaticallyAdjustsContentInsets = false
        let clip = TopAlignedClipView()
        clip.drawsBackground = false
        scroll.contentView = clip

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.userInterfaceLayoutDirection = .leftToRight
        stack.orientation = .vertical
        stack.spacing = 14
        stack.alignment = .leading
        enrolledPageCardsStack = stack
        scroll.documentView = stack

        NSLayoutConstraint.activate([
            stack.leadingAnchor.constraint(equalTo: scroll.contentView.leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: scroll.contentView.trailingAnchor),
            stack.topAnchor.constraint(equalTo: scroll.contentView.topAnchor),
            stack.widthAnchor.constraint(equalTo: scroll.contentView.widthAnchor)
        ])

        contentStack.addArrangedSubview(titleRow)
        contentStack.setCustomSpacing(10, after: titleRow)
        contentStack.addArrangedSubview(heading)
        contentStack.setCustomSpacing(12, after: heading)
        contentStack.addArrangedSubview(scroll)
        panel.addSubview(contentStack)

        NSLayoutConstraint.activate([
            contentStack.leftAnchor.constraint(equalTo: panel.leftAnchor, constant: 28),
            contentStack.rightAnchor.constraint(equalTo: panel.rightAnchor, constant: -28),
            contentStack.topAnchor.constraint(equalTo: panel.topAnchor),
            contentStack.bottomAnchor.constraint(equalTo: panel.bottomAnchor, constant: -16),
            titleRow.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            heading.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            scroll.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            scroll.heightAnchor.constraint(greaterThanOrEqualToConstant: 420)
        ])

        renderEnrolledClassCards([])
        Task { [weak self] in
            await self?.loadEnrolledClasses()
        }

        return panel
    }

    func makeTeachingPageContent() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        panel.userInterfaceLayoutDirection = .leftToRight

        let contentStack = NSStackView()
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        contentStack.userInterfaceLayoutDirection = .leftToRight
        contentStack.orientation = .vertical
        contentStack.spacing = 14
        contentStack.alignment = .width
        contentStack.distribution = .fill

        let titleRow = NSStackView()
        titleRow.translatesAutoresizingMaskIntoConstraints = false
        titleRow.userInterfaceLayoutDirection = .leftToRight
        titleRow.orientation = .horizontal
        titleRow.alignment = .centerY
        titleRow.distribution = .fill
        titleRow.spacing = 10

        let titleLabel = textLabel("Teaching Classes", font: typography.pageTitle, color: palette.textPrimary)
        titleLabel.alignment = .left
        titleLabel.maximumNumberOfLines = 1
        titleLabel.lineBreakMode = .byTruncatingTail
        titleLabel.setContentHuggingPriority(.required, for: .horizontal)
        titleLabel.setContentCompressionResistancePriority(.required, for: .horizontal)

        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false
        spacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
        spacer.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        let refreshButton = makeScheduleRefreshButton()
        refreshButton.target = self
        refreshButton.action = #selector(teachingPageRefreshPressed(_:))

        titleRow.addArrangedSubview(titleLabel)
        titleRow.addArrangedSubview(spacer)
        titleRow.addArrangedSubview(refreshButton)

        let heading = textLabel(teachingPageInitialHeadingText(), font: typography.dateHeading, color: palette.textSecondary)
        heading.alignment = .left
        heading.maximumNumberOfLines = 2
        heading.lineBreakMode = .byWordWrapping
        teachingPageHeadingLabel = heading

        let scroll = NSScrollView()
        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.userInterfaceLayoutDirection = .leftToRight
        scroll.drawsBackground = false
        scroll.hasHorizontalScroller = false
        scroll.hasVerticalScroller = true
        scroll.autohidesScrollers = true
        scroll.borderType = .noBorder
        scroll.scrollerStyle = .overlay
        scroll.automaticallyAdjustsContentInsets = false
        let clip = TopAlignedClipView()
        clip.drawsBackground = false
        scroll.contentView = clip

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.userInterfaceLayoutDirection = .leftToRight
        stack.orientation = .vertical
        stack.spacing = 14
        stack.alignment = .leading
        teachingPageCardsStack = stack
        scroll.documentView = stack

        NSLayoutConstraint.activate([
            stack.leadingAnchor.constraint(equalTo: scroll.contentView.leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: scroll.contentView.trailingAnchor),
            stack.topAnchor.constraint(equalTo: scroll.contentView.topAnchor),
            stack.widthAnchor.constraint(equalTo: scroll.contentView.widthAnchor)
        ])

        contentStack.addArrangedSubview(titleRow)
        contentStack.setCustomSpacing(10, after: titleRow)
        contentStack.addArrangedSubview(heading)
        contentStack.setCustomSpacing(12, after: heading)
        contentStack.addArrangedSubview(scroll)
        panel.addSubview(contentStack)

        NSLayoutConstraint.activate([
            contentStack.leftAnchor.constraint(equalTo: panel.leftAnchor, constant: 28),
            contentStack.rightAnchor.constraint(equalTo: panel.rightAnchor, constant: -28),
            contentStack.topAnchor.constraint(equalTo: panel.topAnchor),
            contentStack.bottomAnchor.constraint(equalTo: panel.bottomAnchor, constant: -16),
            titleRow.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            heading.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            scroll.widthAnchor.constraint(equalTo: contentStack.widthAnchor),
            scroll.heightAnchor.constraint(greaterThanOrEqualToConstant: 420)
        ])

        renderTeachingClassCards([])
        Task { [weak self] in
            await self?.loadTeachingClasses()
        }

        return panel
    }

    func meetJoinSectionRow() -> NSView {
        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.spacing = 12
        row.alignment = .top
        row.distribution = .fillEqually
        row.widthAnchor.constraint(greaterThanOrEqualToConstant: 880).isActive = true
        row.heightAnchor.constraint(equalToConstant: 140).isActive = true

        let instant = HoverSurfaceView()
        instant.translatesAutoresizingMaskIntoConstraints = false
        instant.wantsLayer = true
        instant.layer?.cornerRadius = 14
        instant.layer?.backgroundColor = palette.sectionCard.cgColor
        styleSurface(instant, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let iconWrap = roundedContainer(cornerRadius: 12, color: NSColor.clear)
        iconWrap.translatesAutoresizingMaskIntoConstraints = false
        iconWrap.widthAnchor.constraint(equalToConstant: 58).isActive = true
        iconWrap.heightAnchor.constraint(equalToConstant: 58).isActive = true
        iconWrap.layer?.borderWidth = 0
        let usesClassroomAsset = NSImage(named: "icon_google_classroom") != nil
        let classLogoImage =
            NSImage(named: "icon_google_classroom")
            ?? NSImage(systemSymbolName: "graduationcap.circle.fill", accessibilityDescription: "Google Classroom")
            ?? NSImage()
        classLogoImage.isTemplate = false
        let classLogo = NSImageView(image: classLogoImage)
        classLogo.translatesAutoresizingMaskIntoConstraints = false
        classLogo.imageScaling = .scaleProportionallyDown
        classLogo.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 28, weight: .medium)
        if !usesClassroomAsset {
            classLogo.contentTintColor = palette.primaryBlue
        }
        iconWrap.addSubview(classLogo)

        let instantTitle = textLabel("Open Classroom", font: NSFont.systemFont(ofSize: 40 / 2, weight: .semibold), color: palette.textPrimary)
        let instantSub = textLabel("Go to your classes, assignments,\nand stream in Google Classroom.", font: NSFont.systemFont(ofSize: 16 / 2, weight: .medium), color: palette.textSecondary)
        instantSub.maximumNumberOfLines = 2
        instant.addSubview(iconWrap)
        instant.addSubview(instantTitle)
        instant.addSubview(instantSub)

        let codeCard = HoverSurfaceView()
        codeCard.translatesAutoresizingMaskIntoConstraints = false
        codeCard.wantsLayer = true
        codeCard.layer?.cornerRadius = 14
        codeCard.layer?.backgroundColor = palette.sectionCard.cgColor
        styleSurface(codeCard, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)
        let codeTitle = textLabel("Open class link", font: NSFont.systemFont(ofSize: 40 / 2, weight: .semibold), color: palette.textPrimary)
        let codeInputShell = roundedContainer(cornerRadius: 8, color: palette.inputBackground)
        codeInputShell.translatesAutoresizingMaskIntoConstraints = false
        codeInputShell.heightAnchor.constraint(equalToConstant: 52).isActive = true
        styleSurface(codeInputShell, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)
        let codeField = NSTextField(string: "")
        codeField.translatesAutoresizingMaskIntoConstraints = false
        codeField.isEditable = true
        codeField.isBordered = false
        codeField.drawsBackground = false
        codeField.focusRingType = .none
        codeField.font = NSFont.systemFont(ofSize: 36 / 2, weight: .regular)
        codeField.textColor = palette.textPrimary
        codeField.placeholderString = "Class code or classroom.google.com/…"
        codeInputShell.addSubview(codeField)
        meetLinkField = codeField
        codeCard.addSubview(codeTitle)
        codeCard.addSubview(codeInputShell)

        NSLayoutConstraint.activate([
            classLogo.centerXAnchor.constraint(equalTo: iconWrap.centerXAnchor),
            classLogo.centerYAnchor.constraint(equalTo: iconWrap.centerYAnchor),
            classLogo.widthAnchor.constraint(equalToConstant: 46),
            classLogo.heightAnchor.constraint(equalToConstant: 46),

            iconWrap.leadingAnchor.constraint(equalTo: instant.leadingAnchor, constant: 18),
            iconWrap.topAnchor.constraint(equalTo: instant.topAnchor, constant: 22),
            instantTitle.leadingAnchor.constraint(equalTo: iconWrap.trailingAnchor, constant: 14),
            instantTitle.topAnchor.constraint(equalTo: instant.topAnchor, constant: 24),
            instantSub.leadingAnchor.constraint(equalTo: instantTitle.leadingAnchor),
            instantSub.topAnchor.constraint(equalTo: instantTitle.bottomAnchor, constant: 6),
            instantSub.trailingAnchor.constraint(lessThanOrEqualTo: instant.trailingAnchor, constant: -16),

            codeTitle.leadingAnchor.constraint(equalTo: codeCard.leadingAnchor, constant: 18),
            codeTitle.topAnchor.constraint(equalTo: codeCard.topAnchor, constant: 22),
            codeInputShell.leadingAnchor.constraint(equalTo: codeCard.leadingAnchor, constant: 18),
            codeInputShell.trailingAnchor.constraint(equalTo: codeCard.trailingAnchor, constant: -18),
            codeInputShell.topAnchor.constraint(equalTo: codeTitle.bottomAnchor, constant: 12),
            codeField.leadingAnchor.constraint(equalTo: codeInputShell.leadingAnchor, constant: 14),
            codeField.trailingAnchor.constraint(equalTo: codeInputShell.trailingAnchor, constant: -14),
            codeField.centerYAnchor.constraint(equalTo: codeInputShell.centerYAnchor)
        ])

        let baseColor = palette.sectionCard
        let baseBorderColor = palette.inputBorder
        let classroomHoverTint = NSColor(calibratedRed: 0.46, green: 0.80, blue: 0.42, alpha: 1.0)
        let hoverColor = baseColor.blended(withFraction: darkModeEnabled ? 0.24 : 0.16, of: classroomHoverTint) ?? baseColor
        let hoverBorderColor = baseBorderColor.blended(withFraction: darkModeEnabled ? 0.45 : 0.32, of: classroomHoverTint) ?? baseBorderColor
        instant.onHoverChanged = { [weak self] hovering in
            guard self != nil else { return }
            instant.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            instant.layer?.borderColor = (hovering ? hoverBorderColor : baseBorderColor).cgColor
        }
        codeCard.onHoverChanged = { [weak self] hovering in
            guard self != nil else { return }
            codeCard.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            codeCard.layer?.borderColor = (hovering ? hoverBorderColor : baseBorderColor).cgColor
        }
        instant.onHoverChanged?(false)
        codeCard.onHoverChanged?(false)

        let instantClick = NSClickGestureRecognizer(target: self, action: #selector(instantMeetClicked(_:)))
        instant.addGestureRecognizer(instantClick)
        let joinWithLinkClick = NSClickGestureRecognizer(target: self, action: #selector(joinWithLinkCardClicked(_:)))
        codeCard.addGestureRecognizer(joinWithLinkClick)
        instantMeetCardView = instant
        instantMeetTitleLabel = instantTitle
        instantMeetSubtitleLabel = instantSub
        joinWithLinkCardView = codeCard
        joinWithLinkTitleLabel = codeTitle
        refreshInstantMeetPremiumState()

        row.addArrangedSubview(instant)
        row.addArrangedSubview(codeCard)
        return row
    }

    func meetJoinActionsRow() -> NSView {
        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.spacing = 12
        row.alignment = .centerY
        row.widthAnchor.constraint(greaterThanOrEqualToConstant: 880).isActive = true

        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false
        row.addArrangedSubview(spacer)
        row.addArrangedSubview(meetActionButton(
            title: "Cancel",
            color: palette.cancelButton,
            textColor: palette.textSecondary,
            width: 110,
            action: #selector(cancelMeetJoinClicked(_:))
        ))
        let joinButton = meetActionButton(
            title: "Open",
            color: palette.primaryBlue,
            textColor: .white,
            width: 116,
            action: #selector(joinMeetClicked(_:))
        )
        joinMeetPrimaryButton = joinButton
        row.addArrangedSubview(joinButton)
        refreshInstantMeetPremiumState()
        return row
    }

    func meetActionButton(title: String, color: NSColor, textColor: NSColor, width: CGFloat, action: Selector) -> NSButton {
        let button = HoverButton(title: title, target: self, action: action)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = 9
        let baseBackground = color
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverBackground = baseBackground.blended(withFraction: 0.10, of: hoverBlend) ?? baseBackground

        let baseBorder = (title == "Cancel" ? palette.inputBorder : palette.primaryBlueBorder)
        let hoverBorder = baseBorder.blended(withFraction: 0.18, of: hoverBlend) ?? baseBorder

        button.layer?.backgroundColor = baseBackground.cgColor
        button.layer?.borderColor = baseBorder.cgColor
        button.layer?.borderWidth = 1
        button.font = typography.buttonText
        button.contentTintColor = textColor
        button.widthAnchor.constraint(equalToConstant: width).isActive = true
        button.heightAnchor.constraint(equalToConstant: 36).isActive = true
        button.onHoverChanged = { [weak self, weak button] hovering in
            guard let self, let button else { return }
            button.layer?.backgroundColor = (hovering ? hoverBackground : baseBackground).cgColor
            button.layer?.borderColor = (hovering ? hoverBorder : baseBorder).cgColor
            if title == "Cancel" {
                button.contentTintColor = hovering ? (self.darkModeEnabled ? .white : self.palette.textPrimary) : textColor
            }
        }
        button.onHoverChanged?(false)
        return button
    }

    func makePaywallContent() -> NSView {
        paywallPlanViews.removeAll()
        premiumPlanByView.removeAll()

        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        panel.wantsLayer = true
        panel.layer?.backgroundColor = palette.pageBackground.cgColor

        let contentStack = NSStackView()
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        contentStack.orientation = .vertical
        contentStack.spacing = 12
        contentStack.distribution = .fill
        contentStack.alignment = .centerX
        panel.addSubview(contentStack)
        let paywallLayoutWidth: CGFloat = 980

        let topRow = NSStackView()
        topRow.translatesAutoresizingMaskIntoConstraints = false
        topRow.orientation = .horizontal
        topRow.alignment = .centerY
        topRow.distribution = .fill
        topRow.spacing = 10
        topRow.addArrangedSubview(textLabel("Classroom Pro", font: NSFont.systemFont(ofSize: 27, weight: .bold), color: palette.textPrimary))
        let closeButton = HoverButton(title: "✕", target: self, action: #selector(closePaywallClicked(_:)))
        closeButton.translatesAutoresizingMaskIntoConstraints = false
        closeButton.isBordered = false
        closeButton.bezelStyle = .regularSquare
        closeButton.wantsLayer = true
        closeButton.layer?.cornerRadius = 14
        closeButton.layer?.backgroundColor = palette.inputBackground.cgColor
        closeButton.layer?.borderColor = palette.inputBorder.cgColor
        closeButton.layer?.borderWidth = 1
        closeButton.font = typography.iconButton
        closeButton.contentTintColor = palette.textSecondary
        closeButton.widthAnchor.constraint(equalToConstant: 28).isActive = true
        closeButton.heightAnchor.constraint(equalToConstant: 28).isActive = true
        closeButton.onHoverChanged = { [weak closeButton, weak self] hovering in
            guard let closeButton, let self else { return }
            let base = self.palette.inputBackground
            let hoverBlend = self.darkModeEnabled ? NSColor.white : NSColor.black
            let hover = base.blended(withFraction: 0.10, of: hoverBlend) ?? base
            closeButton.layer?.backgroundColor = (hovering ? hover : base).cgColor
            closeButton.contentTintColor = hovering ? (self.darkModeEnabled ? .white : self.palette.textPrimary) : self.palette.textSecondary
        }
        panel.addSubview(closeButton)
        contentStack.addArrangedSubview(topRow)
        topRow.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true

        let hero = roundedContainer(cornerRadius: 16, color: palette.sectionCard)
        hero.translatesAutoresizingMaskIntoConstraints = false
        styleSurface(hero, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)
        contentStack.addArrangedSubview(hero)
        hero.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true

        let heroBadge = textLabel("PREMIUM EXPERIENCE", font: NSFont.systemFont(ofSize: 10, weight: .bold), color: NSColor(calibratedRed: 0.42, green: 0.93, blue: 0.70, alpha: 1))
        hero.addSubview(heroBadge)

        let heroTitle = textLabel("Elevate your classroom experience", font: NSFont.systemFont(ofSize: 22, weight: .bold), color: palette.textPrimary)
        let heroSubtitle = textLabel("Unlock intelligent automation, deep analytics, and premium support for modern educators.", font: NSFont.systemFont(ofSize: 13, weight: .medium), color: palette.textSecondary)
        heroTitle.maximumNumberOfLines = 2
        heroSubtitle.maximumNumberOfLines = 3
        hero.addSubview(heroTitle)
        hero.addSubview(heroSubtitle)
        NSLayoutConstraint.activate([
            heroBadge.leadingAnchor.constraint(equalTo: hero.leadingAnchor, constant: 16),
            heroBadge.topAnchor.constraint(equalTo: hero.topAnchor, constant: 14),
            heroTitle.leadingAnchor.constraint(equalTo: hero.leadingAnchor, constant: 16),
            heroTitle.trailingAnchor.constraint(lessThanOrEqualTo: hero.trailingAnchor, constant: -16),
            heroTitle.topAnchor.constraint(equalTo: heroBadge.bottomAnchor, constant: 10),
            heroSubtitle.leadingAnchor.constraint(equalTo: heroTitle.leadingAnchor),
            heroSubtitle.trailingAnchor.constraint(equalTo: hero.trailingAnchor, constant: -16),
            heroSubtitle.topAnchor.constraint(equalTo: heroTitle.bottomAnchor, constant: 8),
            heroSubtitle.bottomAnchor.constraint(equalTo: hero.bottomAnchor, constant: -16)
        ])

        let benefitsRow = NSStackView()
        benefitsRow.translatesAutoresizingMaskIntoConstraints = false
        benefitsRow.orientation = .horizontal
        benefitsRow.spacing = 8
        benefitsRow.distribution = .fillEqually
        benefitsRow.alignment = .centerY
        benefitsRow.addArrangedSubview(paywallBenefitItem(icon: "📅", text: "Manage classes"))
        benefitsRow.addArrangedSubview(paywallBenefitItem(icon: "🧠", text: "Smart to-dos"))
        benefitsRow.addArrangedSubview(paywallBenefitItem(icon: "⚡", text: "Faster workflow"))
        benefitsRow.addArrangedSubview(paywallBenefitItem(icon: "🛟", text: "Priority support"))
        contentStack.addArrangedSubview(benefitsRow)
        benefitsRow.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true

        let plansRow = NSStackView()
        plansRow.translatesAutoresizingMaskIntoConstraints = false
        plansRow.orientation = .horizontal
        plansRow.spacing = 10
        plansRow.distribution = .fillEqually
        plansRow.alignment = .centerY

        let weeklyCard = paywallPlanCard(
            title: "Weekly",
            price: "PKR 1,100.00",
            badge: "Basic",
            badgeColor: NSColor(calibratedRed: 1.0, green: 0.60, blue: 0.20, alpha: 1),
            subtitle: nil,
            plan: .weekly,
            strikePrice: nil
        )
        let monthlyCard = paywallPlanCard(
            title: "Monthly",
            price: "PKR 2,500.00",
            badge: "Popular",
            badgeColor: NSColor(calibratedRed: 0.19, green: 0.82, blue: 0.39, alpha: 1),
            subtitle: "625.00/week",
            plan: .monthly,
            strikePrice: nil
        )
        let yearlyCard = paywallPlanCard(
            title: "Yearly",
            price: "PKR 9,900.00",
            badge: "Best Value",
            badgeColor: NSColor(calibratedRed: 1.0, green: 0.60, blue: 0.20, alpha: 1),
            subtitle: "190.38/week",
            plan: .yearly,
            strikePrice: nil
        )
        let lifetimeCard = paywallPlanCard(
            title: "Lifetime",
            price: "PKR 14,900.00",
            badge: "Save 50%",
            badgeColor: NSColor(calibratedRed: 1.0, green: 0.60, blue: 0.20, alpha: 1),
            subtitle: nil,
            plan: .lifetime,
            strikePrice: "PKR 29,800.00"
        )
        plansRow.addArrangedSubview(weeklyCard)
        plansRow.addArrangedSubview(monthlyCard)
        plansRow.addArrangedSubview(yearlyCard)
        plansRow.addArrangedSubview(lifetimeCard)
        contentStack.addArrangedSubview(plansRow)
        plansRow.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true
        updatePaywallPlanSelection()

        let trustRow = NSStackView()
        trustRow.translatesAutoresizingMaskIntoConstraints = false
        trustRow.orientation = .horizontal
        trustRow.spacing = 8
        trustRow.distribution = .fillEqually
        trustRow.alignment = .centerY
        trustRow.addArrangedSubview(paywallMetaItem(title: "Cancel anytime", subtitle: "No lock-in"))
        trustRow.addArrangedSubview(paywallMetaItem(title: "Instant access", subtitle: "Unlock all tools"))
        trustRow.addArrangedSubview(paywallMetaItem(title: "Secure billing", subtitle: "Handled by Apple"))
        contentStack.addArrangedSubview(trustRow)
        trustRow.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true

        let offer = textLabel(paywallOfferText(for: selectedPremiumPlan), font: NSFont.systemFont(ofSize: 13, weight: .semibold), color: palette.textPrimary)
        offer.alignment = .center
        paywallOfferLabel = offer
        let offerWrap = NSView()
        offerWrap.translatesAutoresizingMaskIntoConstraints = false
        offerWrap.addSubview(offer)
        contentStack.addArrangedSubview(offerWrap)
        offerWrap.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true
        NSLayoutConstraint.activate([
            offer.centerXAnchor.constraint(equalTo: offerWrap.centerXAnchor),
            offer.topAnchor.constraint(equalTo: offerWrap.topAnchor, constant: 4),
            offer.bottomAnchor.constraint(equalTo: offerWrap.bottomAnchor, constant: -2)
        ])

        let continueButton = HoverButton(title: "", target: self, action: #selector(paywallContinueClicked(_:)))
        continueButton.translatesAutoresizingMaskIntoConstraints = false
        continueButton.isBordered = false
        continueButton.bezelStyle = .regularSquare
        continueButton.wantsLayer = true
        continueButton.layer?.cornerRadius = 14
        continueButton.layer?.backgroundColor = palette.primaryBlue.cgColor
        continueButton.heightAnchor.constraint(equalToConstant: 44).isActive = true
        styleSurface(continueButton, borderColor: palette.primaryBlueBorder, borderWidth: 1, shadow: true)
        let continueLabel = textLabel("Continue", font: NSFont.systemFont(ofSize: 16, weight: .bold), color: .white)
        continueButton.addSubview(continueLabel)
        NSLayoutConstraint.activate([
            continueLabel.centerXAnchor.constraint(equalTo: continueButton.centerXAnchor),
            continueLabel.centerYAnchor.constraint(equalTo: continueButton.centerYAnchor)
        ])
        let baseBlue = palette.primaryBlue
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverBlue = baseBlue.blended(withFraction: 0.10, of: hoverBlend) ?? baseBlue
        continueButton.onHoverChanged = { hovering in
            continueButton.layer?.backgroundColor = (hovering ? hoverBlue : baseBlue).cgColor
        }
        continueButton.onHoverChanged?(false)
        paywallContinueButton = continueButton
        paywallContinueLabel = continueLabel
        contentStack.addArrangedSubview(continueButton)
        continueButton.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true

        let secure = textLabel("Secured by Apple. Cancel anytime.", font: NSFont.systemFont(ofSize: 12, weight: .semibold), color: palette.textSecondary)
        secure.alignment = .center
        let secureWrap = NSView()
        secureWrap.translatesAutoresizingMaskIntoConstraints = false
        secureWrap.addSubview(secure)
        contentStack.addArrangedSubview(secureWrap)
        secureWrap.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true
        NSLayoutConstraint.activate([
            secure.centerXAnchor.constraint(equalTo: secureWrap.centerXAnchor),
            secure.topAnchor.constraint(equalTo: secureWrap.topAnchor, constant: 2),
            secure.bottomAnchor.constraint(equalTo: secureWrap.bottomAnchor, constant: -4)
        ])

        let footer = paywallFooterLinks()
        contentStack.addArrangedSubview(footer)
        footer.widthAnchor.constraint(equalTo: contentStack.widthAnchor).isActive = true

        NSLayoutConstraint.activate([
            closeButton.topAnchor.constraint(equalTo: panel.topAnchor, constant: 18),
            closeButton.trailingAnchor.constraint(equalTo: panel.trailingAnchor, constant: -18),
            contentStack.centerXAnchor.constraint(equalTo: panel.centerXAnchor),
            contentStack.widthAnchor.constraint(equalToConstant: paywallLayoutWidth),
            contentStack.topAnchor.constraint(equalTo: panel.topAnchor, constant: 80),
            contentStack.bottomAnchor.constraint(equalTo: panel.bottomAnchor, constant: -12)
        ])

        refreshPaywallStoreUI()
        return panel
    }

    func paywallPlanCard(
        title: String,
        price: String,
        badge: String,
        badgeColor: NSColor,
        subtitle: String?,
        plan: PremiumPlan,
        strikePrice: String?
    ) -> NSView {
        let wrapper = HoverButton(title: "", target: self, action: #selector(paywallPlanButtonClicked(_:)))
        wrapper.translatesAutoresizingMaskIntoConstraints = false
        wrapper.isBordered = false
        wrapper.bezelStyle = .regularSquare
        wrapper.wantsLayer = true
        wrapper.layer?.backgroundColor = NSColor.clear.cgColor
        wrapper.widthAnchor.constraint(greaterThanOrEqualToConstant: 160).isActive = true
        wrapper.heightAnchor.constraint(equalToConstant: 162).isActive = true
        wrapper.tag = plan.rawValue

        let card = HoverTrackingView()
        card.translatesAutoresizingMaskIntoConstraints = false
        card.wantsLayer = true
        card.layer?.cornerRadius = 16
        card.layer?.backgroundColor = palette.sectionCard.cgColor
        card.heightAnchor.constraint(equalToConstant: 150).isActive = true
        wrapper.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            card.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            card.topAnchor.constraint(equalTo: wrapper.topAnchor, constant: 12),
            card.bottomAnchor.constraint(equalTo: wrapper.bottomAnchor)
        ])
        styleSurface(card, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let badgeLabel = textLabel(badge, font: NSFont.systemFont(ofSize: 10, weight: .bold), color: .white)
        let badgeWrap = roundedContainer(cornerRadius: 10, color: badgeColor)
        badgeWrap.translatesAutoresizingMaskIntoConstraints = false
        badgeWrap.wantsLayer = true
        badgeWrap.layer?.borderColor = NSColor(calibratedWhite: 1, alpha: 0.22).cgColor
        badgeWrap.layer?.borderWidth = 1
        badgeWrap.layer?.shadowColor = NSColor.black.cgColor
        badgeWrap.layer?.shadowOpacity = 0.20
        badgeWrap.layer?.shadowOffset = CGSize(width: 0, height: -1)
        badgeWrap.layer?.shadowRadius = 3
        badgeWrap.addSubview(badgeLabel)
        NSLayoutConstraint.activate([
            badgeLabel.leadingAnchor.constraint(equalTo: badgeWrap.leadingAnchor, constant: 8),
            badgeLabel.trailingAnchor.constraint(equalTo: badgeWrap.trailingAnchor, constant: -8),
            badgeLabel.topAnchor.constraint(equalTo: badgeWrap.topAnchor, constant: 2),
            badgeLabel.bottomAnchor.constraint(equalTo: badgeWrap.bottomAnchor, constant: -2)
        ])
        wrapper.addSubview(badgeWrap)

        let titleLabel = textLabel(title, font: NSFont.systemFont(ofSize: 15, weight: .bold), color: palette.primaryBlue)
        card.addSubview(titleLabel)
        let priceLabel = textLabel(price, font: NSFont.systemFont(ofSize: 12, weight: .bold), color: palette.textPrimary)
        card.addSubview(priceLabel)
        paywallPriceLabels[plan] = priceLabel

        NSLayoutConstraint.activate([
            badgeWrap.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 12),
            badgeWrap.centerYAnchor.constraint(equalTo: card.topAnchor),

            titleLabel.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 12),
            titleLabel.topAnchor.constraint(equalTo: card.topAnchor, constant: 34),

            priceLabel.leadingAnchor.constraint(equalTo: titleLabel.leadingAnchor),
            priceLabel.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 10),
            priceLabel.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -12)
        ])

        if let subtitle {
            let sub = textLabel(subtitle, font: NSFont.systemFont(ofSize: 10, weight: .semibold), color: palette.textSecondary)
            card.addSubview(sub)
            paywallSubtitleLabels[plan] = sub
            NSLayoutConstraint.activate([
                sub.leadingAnchor.constraint(equalTo: priceLabel.leadingAnchor),
                sub.topAnchor.constraint(equalTo: priceLabel.bottomAnchor, constant: 2),
                sub.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -12)
            ])
        }

        if let strikePrice {
            let strike = textLabel(strikePrice, font: NSFont.systemFont(ofSize: 12, weight: .medium), color: NSColor.systemRed)
            card.addSubview(strike)
            NSLayoutConstraint.activate([
                strike.leadingAnchor.constraint(equalTo: priceLabel.leadingAnchor),
                strike.topAnchor.constraint(equalTo: priceLabel.bottomAnchor, constant: 4),
                strike.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -12)
            ])
        }

        paywallPlanViews[plan] = card
        wrapper.onHoverChanged = { [weak self, weak card] hovering in
            guard let self, let card else { return }
            self.applyPaywallPlanStyle(card, isSelected: plan == self.selectedPremiumPlan, hovering: hovering)
        }
        wrapper.onHoverChanged?(false)

        return wrapper
    }

    func paywallFooterLinks() -> NSView {
        let wrap = NSView()
        wrap.translatesAutoresizingMaskIntoConstraints = false
        wrap.heightAnchor.constraint(equalToConstant: 40).isActive = true

        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.distribution = .fillEqually
        row.alignment = .centerY
        row.spacing = 0
        wrap.addSubview(row)

        row.addArrangedSubview(footerLink("Privacy Policy"))
        row.addArrangedSubview(footerLink("Support"))
        row.addArrangedSubview(footerLink("Terms of Services"))

        NSLayoutConstraint.activate([
            row.leadingAnchor.constraint(equalTo: wrap.leadingAnchor),
            row.trailingAnchor.constraint(equalTo: wrap.trailingAnchor),
            row.topAnchor.constraint(equalTo: wrap.topAnchor),
            row.bottomAnchor.constraint(equalTo: wrap.bottomAnchor)
        ])

        return wrap
    }

    func footerLink(_ title: String) -> NSView {
        let container = HoverTrackingView()
        container.translatesAutoresizingMaskIntoConstraints = false
        let label = textLabel(title, font: NSFont.systemFont(ofSize: 12, weight: .semibold), color: palette.textSecondary)
        label.alignment = .center
        container.addSubview(label)

        NSLayoutConstraint.activate([
            label.centerXAnchor.constraint(equalTo: container.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: container.centerYAnchor)
        ])

        let click = NSClickGestureRecognizer(target: self, action: #selector(paywallFooterLinkClicked(_:)))
        container.addGestureRecognizer(click)
        container.onHoverChanged = { hovering in
            label.textColor = hovering ? (self.darkModeEnabled ? .white : self.palette.textPrimary) : self.palette.textSecondary
        }
        container.onHoverChanged?(false)
        return container
    }

    func paywallBenefitsSection() -> NSView {
        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.orientation = .vertical
        stack.spacing = 8
        stack.alignment = .leading
        stack.widthAnchor.constraint(greaterThanOrEqualToConstant: paywallContentWidth).isActive = true

        let rowOne = NSStackView()
        rowOne.translatesAutoresizingMaskIntoConstraints = false
        rowOne.orientation = .horizontal
        rowOne.spacing = 10
        rowOne.distribution = .fillEqually
        rowOne.alignment = .centerY
        rowOne.addArrangedSubview(paywallBenefitItem(icon: "📅", text: "Classes & to-do"))
        rowOne.addArrangedSubview(paywallBenefitItem(icon: "🖼️", text: "Virtual backgrounds"))

        let rowTwo = NSStackView()
        rowTwo.translatesAutoresizingMaskIntoConstraints = false
        rowTwo.orientation = .horizontal
        rowTwo.spacing = 10
        rowTwo.distribution = .fillEqually
        rowTwo.alignment = .centerY
        rowTwo.addArrangedSubview(paywallBenefitItem(icon: "⚡", text: "Tools for productivity"))
        rowTwo.addArrangedSubview(paywallBenefitItem(icon: "🛟", text: "24/7 support"))

        stack.addArrangedSubview(rowOne)
        stack.addArrangedSubview(rowTwo)
        return stack
    }

    func paywallMetaItem(title: String, subtitle: String) -> NSView {
        let card = roundedContainer(cornerRadius: 12, color: palette.inputBackground)
        card.translatesAutoresizingMaskIntoConstraints = false
        card.heightAnchor.constraint(equalToConstant: 48).isActive = true
        styleSurface(card, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let titleLabel = textLabel(title, font: NSFont.systemFont(ofSize: 11, weight: .semibold), color: palette.textPrimary)
        let subtitleLabel = textLabel(subtitle, font: NSFont.systemFont(ofSize: 10, weight: .medium), color: palette.textSecondary)
        card.addSubview(titleLabel)
        card.addSubview(subtitleLabel)

        NSLayoutConstraint.activate([
            titleLabel.centerXAnchor.constraint(equalTo: card.centerXAnchor),
            titleLabel.topAnchor.constraint(equalTo: card.topAnchor, constant: 8),
            subtitleLabel.centerXAnchor.constraint(equalTo: card.centerXAnchor),
            subtitleLabel.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 3)
        ])

        return card
    }

    func paywallBenefitItem(icon: String, text: String) -> NSView {
        let card = HoverTrackingView()
        card.translatesAutoresizingMaskIntoConstraints = false
        card.wantsLayer = true
        card.layer?.cornerRadius = 10
        card.layer?.backgroundColor = palette.inputBackground.cgColor
        card.heightAnchor.constraint(equalToConstant: 44).isActive = true
        styleSurface(card, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let iconWrap = roundedContainer(cornerRadius: 8, color: palette.inputBackground)
        iconWrap.translatesAutoresizingMaskIntoConstraints = false
        iconWrap.widthAnchor.constraint(equalToConstant: 24).isActive = true
        iconWrap.heightAnchor.constraint(equalToConstant: 24).isActive = true
        styleSurface(iconWrap, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let iconLabel = textLabel(icon, font: NSFont.systemFont(ofSize: 12, weight: .medium), color: palette.primaryBlue)
        iconWrap.addSubview(iconLabel)
        NSLayoutConstraint.activate([
            iconLabel.centerXAnchor.constraint(equalTo: iconWrap.centerXAnchor),
            iconLabel.centerYAnchor.constraint(equalTo: iconWrap.centerYAnchor)
        ])

        let title = textLabel(text, font: NSFont.systemFont(ofSize: 11, weight: .medium), color: palette.textPrimary)

        card.addSubview(iconWrap)
        card.addSubview(title)
        NSLayoutConstraint.activate([
            iconWrap.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 8),
            iconWrap.centerYAnchor.constraint(equalTo: card.centerYAnchor),
            title.leadingAnchor.constraint(equalTo: iconWrap.trailingAnchor, constant: 10),
            title.centerYAnchor.constraint(equalTo: card.centerYAnchor),
            title.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -8)
        ])

        let base = palette.inputBackground
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hover = base.blended(withFraction: 0.10, of: hoverBlend) ?? base
        let hoverBorder = palette.primaryBlueBorder.withAlphaComponent(0.55)
        card.onHoverChanged = { [weak card, weak iconWrap] hovering in
            guard let card else { return }
            card.layer?.backgroundColor = (hovering ? hover : base).cgColor
            card.layer?.borderColor = (hovering ? hoverBorder : self.palette.inputBorder).cgColor
            iconWrap?.layer?.borderColor = (hovering ? hoverBorder : self.palette.inputBorder).cgColor
        }
        card.onHoverChanged?(false)
        return card
    }

    func zoomJoinModeTabs() -> NSView {
        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.alignment = .centerY
        row.spacing = 28
        row.widthAnchor.constraint(greaterThanOrEqualToConstant: 780).isActive = true

        let idTab = joinModeTab("Join with ID", mode: .id)
        let urlTab = joinModeTab("Join with URL", mode: .url)
        row.addArrangedSubview(idTab)
        row.addArrangedSubview(urlTab)
        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false
        row.addArrangedSubview(spacer)

        zoomJoinModeViews[.id] = idTab
        zoomJoinModeViews[.url] = urlTab
        updateZoomJoinModeAppearance()
        return row
    }

    func joinModeTab(_ title: String, mode: ZoomJoinMode) -> NSView {
        let tab = HoverTrackingView()
        tab.translatesAutoresizingMaskIntoConstraints = false
        tab.wantsLayer = true
        tab.layer?.cornerRadius = 6
        tab.layer?.backgroundColor = NSColor.clear.cgColor
        tab.heightAnchor.constraint(equalToConstant: 30).isActive = true
        zoomJoinModeByView[ObjectIdentifier(tab)] = mode

        let label = textLabel(title, font: NSFont.systemFont(ofSize: 33 / 2, weight: .medium), color: palette.textPrimary)
        tab.addSubview(label)
        NSLayoutConstraint.activate([
            label.leadingAnchor.constraint(equalTo: tab.leadingAnchor, constant: 4),
            label.trailingAnchor.constraint(equalTo: tab.trailingAnchor, constant: -4),
            label.topAnchor.constraint(equalTo: tab.topAnchor, constant: 4),
            label.bottomAnchor.constraint(equalTo: tab.bottomAnchor, constant: -6)
        ])

        let click = NSClickGestureRecognizer(target: self, action: #selector(zoomJoinModeClicked(_:)))
        tab.addGestureRecognizer(click)
        return tab
    }

    func updateZoomJoinModeAppearance() {
        for (mode, tab) in zoomJoinModeViews {
            let selected = (mode == selectedZoomJoinMode)
            let textColor = selected ? palette.textPrimary : palette.textSecondary
            let label = tab.subviews.first { $0 is NSTextField } as? NSTextField
            label?.textColor = textColor

            // Keep the active tab visually underlined like the reference.
            if selected {
                if tab.subviews.contains(where: { $0.identifier?.rawValue == "modeUnderline" }) == false {
                    let underline = NSView()
                    underline.identifier = NSUserInterfaceItemIdentifier("modeUnderline")
                    underline.translatesAutoresizingMaskIntoConstraints = false
                    underline.wantsLayer = true
                    underline.layer?.backgroundColor = palette.primaryBlue.cgColor
                    tab.addSubview(underline)
                    NSLayoutConstraint.activate([
                        underline.leadingAnchor.constraint(equalTo: tab.leadingAnchor),
                        underline.trailingAnchor.constraint(equalTo: tab.trailingAnchor),
                        underline.bottomAnchor.constraint(equalTo: tab.bottomAnchor),
                        underline.heightAnchor.constraint(equalToConstant: 2)
                    ])
                }
            } else {
                tab.subviews
                    .filter { $0.identifier?.rawValue == "modeUnderline" }
                    .forEach { $0.removeFromSuperview() }
            }
        }
    }

    func joinWithIDHeading() -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false

        let title = textLabel("Join with ID", font: typography.joinWithURLTitle, color: palette.textPrimary)
        title.alignment = .left
        title.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        title.setContentCompressionResistancePriority(.required, for: .horizontal)

        let bar = NSView()
        bar.translatesAutoresizingMaskIntoConstraints = false
        bar.wantsLayer = true
        bar.layer?.backgroundColor = palette.primaryBlue.cgColor
        bar.heightAnchor.constraint(equalToConstant: 3).isActive = true

        container.addSubview(title)
        container.addSubview(bar)

        NSLayoutConstraint.activate([
            title.leadingAnchor.constraint(equalTo: container.leadingAnchor),
            title.topAnchor.constraint(equalTo: container.topAnchor),

            bar.leadingAnchor.constraint(equalTo: title.leadingAnchor),
            bar.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 6),
            bar.widthAnchor.constraint(equalTo: title.widthAnchor),
            bar.bottomAnchor.constraint(equalTo: container.bottomAnchor),

            container.trailingAnchor.constraint(equalTo: title.trailingAnchor)
        ])

        return container
    }

    func zoomMeetingIDSection() -> NSView {
        let wrapper = NSView()
        wrapper.translatesAutoresizingMaskIntoConstraints = false

        let fieldsRow = NSStackView()
        fieldsRow.translatesAutoresizingMaskIntoConstraints = false
        fieldsRow.orientation = .horizontal
        fieldsRow.alignment = .top
        fieldsRow.distribution = .fillEqually
        fieldsRow.spacing = 12
        fieldsRow.addArrangedSubview(zoomInputField(title: "Meeting ID", placeholder: "Enter meeting ID..."))
        fieldsRow.addArrangedSubview(zoomInputField(title: "Meeting Passcode", placeholder: "Enter meeting passcode..."))

        let actions = NSStackView()
        actions.orientation = .horizontal
        actions.spacing = 10
        actions.translatesAutoresizingMaskIntoConstraints = false
        actions.alignment = .centerY
        actions.addArrangedSubview(actionButton(title: "Cancel", color: palette.cancelButton, textColor: palette.textSecondary, width: 110))
        actions.addArrangedSubview(actionButton(title: "Join", color: palette.primaryBlue, textColor: .white, width: 116))

        wrapper.addSubview(fieldsRow)
        wrapper.addSubview(actions)

        NSLayoutConstraint.activate([
            wrapper.widthAnchor.constraint(greaterThanOrEqualToConstant: 780),

            fieldsRow.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            fieldsRow.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            fieldsRow.topAnchor.constraint(equalTo: wrapper.topAnchor),

            actions.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            actions.topAnchor.constraint(equalTo: fieldsRow.bottomAnchor, constant: 14),
            actions.bottomAnchor.constraint(equalTo: wrapper.bottomAnchor)
        ])

        return wrapper
    }

    func zoomInputField(title: String, placeholder: String) -> NSView {
        let wrapper = NSView()
        wrapper.translatesAutoresizingMaskIntoConstraints = false

        let heading = textLabel(title, font: typography.fieldLabel, color: palette.textPrimary)
        let textFieldContainer = roundedContainer(cornerRadius: 10, color: palette.inputBackground)
        textFieldContainer.translatesAutoresizingMaskIntoConstraints = false
        textFieldContainer.heightAnchor.constraint(equalToConstant: 40).isActive = true
        styleSurface(textFieldContainer, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let field = NSTextField(string: "")
        field.translatesAutoresizingMaskIntoConstraints = false
        field.isEditable = true
        field.isSelectable = true
        field.isBordered = false
        field.drawsBackground = false
        field.placeholderString = placeholder
        field.font = typography.inputPlaceholder
        field.textColor = palette.textPrimary
        field.focusRingType = .none
        textFieldContainer.addSubview(field)

        wrapper.addSubview(heading)
        wrapper.addSubview(textFieldContainer)

        NSLayoutConstraint.activate([
            heading.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            heading.topAnchor.constraint(equalTo: wrapper.topAnchor),

            textFieldContainer.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            textFieldContainer.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            textFieldContainer.topAnchor.constraint(equalTo: heading.bottomAnchor, constant: 10),
            textFieldContainer.bottomAnchor.constraint(equalTo: wrapper.bottomAnchor),

            field.leadingAnchor.constraint(equalTo: textFieldContainer.leadingAnchor, constant: 12),
            field.trailingAnchor.constraint(equalTo: textFieldContainer.trailingAnchor, constant: -12),
            field.centerYAnchor.constraint(equalTo: textFieldContainer.centerYAnchor)
        ])

        return wrapper
    }

    func joinWithURLHeading() -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false

        let title = textLabel("Join with URL", font: typography.joinWithURLTitle, color: palette.textPrimary)
        title.alignment = .left
        title.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        title.setContentCompressionResistancePriority(.required, for: .horizontal)

        let bar = NSView()
        bar.translatesAutoresizingMaskIntoConstraints = false
        bar.wantsLayer = true
        bar.layer?.backgroundColor = palette.primaryBlue.cgColor
        bar.heightAnchor.constraint(equalToConstant: 3).isActive = true

        container.addSubview(title)
        container.addSubview(bar)

        NSLayoutConstraint.activate([
            title.leadingAnchor.constraint(equalTo: container.leadingAnchor),
            title.topAnchor.constraint(equalTo: container.topAnchor),

            bar.leadingAnchor.constraint(equalTo: title.leadingAnchor),
            bar.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 6),
            bar.widthAnchor.constraint(equalTo: title.widthAnchor),
            bar.bottomAnchor.constraint(equalTo: container.bottomAnchor),

            container.trailingAnchor.constraint(equalTo: title.trailingAnchor)
        ])

        return container
    }

    func meetingUrlSection() -> NSView {
        let wrapper = NSView()
        wrapper.translatesAutoresizingMaskIntoConstraints = false

        let title = textLabel("Meeting URL", font: typography.fieldLabel, color: palette.textSecondary)
        let textFieldContainer = roundedContainer(cornerRadius: 10, color: palette.inputBackground)
        textFieldContainer.translatesAutoresizingMaskIntoConstraints = false
        textFieldContainer.heightAnchor.constraint(equalToConstant: 40).isActive = true
        styleSurface(textFieldContainer, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let urlField = NSTextField(string: "")
        urlField.translatesAutoresizingMaskIntoConstraints = false
        urlField.isEditable = true
        urlField.isSelectable = true
        urlField.isBordered = false
        urlField.drawsBackground = false
        urlField.placeholderString = "Enter meeting URL..."
        urlField.font = typography.inputPlaceholder
        urlField.textColor = palette.textPrimary
        urlField.focusRingType = .none
        textFieldContainer.addSubview(urlField)

        let actions = NSStackView()
        actions.orientation = .horizontal
        actions.spacing = 10
        actions.translatesAutoresizingMaskIntoConstraints = false
        actions.alignment = .centerY
        actions.addArrangedSubview(actionButton(title: "Cancel", color: palette.cancelButton, textColor: palette.textSecondary, width: 110))
        actions.addArrangedSubview(actionButton(title: "Join", color: palette.primaryBlue, textColor: .white, width: 116))

        wrapper.addSubview(title)
        wrapper.addSubview(textFieldContainer)
        wrapper.addSubview(actions)

        NSLayoutConstraint.activate([
            wrapper.widthAnchor.constraint(greaterThanOrEqualToConstant: 780),

            title.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            title.topAnchor.constraint(equalTo: wrapper.topAnchor),

            textFieldContainer.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            textFieldContainer.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            textFieldContainer.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 10),

            urlField.leadingAnchor.constraint(equalTo: textFieldContainer.leadingAnchor, constant: 12),
            urlField.trailingAnchor.constraint(equalTo: textFieldContainer.trailingAnchor, constant: -12),
            urlField.centerYAnchor.constraint(equalTo: textFieldContainer.centerYAnchor),

            actions.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            actions.topAnchor.constraint(equalTo: textFieldContainer.bottomAnchor, constant: 14),
            actions.bottomAnchor.constraint(equalTo: wrapper.bottomAnchor)
        ])

        return wrapper
    }

    func scheduleHeader() -> NSView {
        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.alignment = .centerY
        row.distribution = .fill
        row.spacing = 12

        row.addArrangedSubview(textLabel("To-do", font: typography.sectionTitleBold, color: palette.textPrimary))

        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false
        row.addArrangedSubview(spacer)
        spacer.setContentHuggingPriority(.defaultLow, for: .horizontal)

        row.addArrangedSubview(makeScheduleRefreshButton())

        row.addArrangedSubview(makeScheduleFilterDropdown())
        row.widthAnchor.constraint(greaterThanOrEqualToConstant: 780).isActive = true
        return row
    }

    private func schedulePageHeader() -> NSView {
        let container = NSStackView()
        container.translatesAutoresizingMaskIntoConstraints = false
        container.userInterfaceLayoutDirection = .leftToRight
        container.orientation = .vertical
        container.spacing = 8
        container.alignment = .width

        let titleRow = NSStackView()
        titleRow.translatesAutoresizingMaskIntoConstraints = false
        titleRow.userInterfaceLayoutDirection = .leftToRight
        titleRow.orientation = .horizontal
        titleRow.alignment = .centerY
        titleRow.distribution = .fill
        titleRow.spacing = 0

        let titleLabel = textLabel("To-do", font: typography.pageTitle, color: palette.textPrimary)
        titleLabel.alignment = .left
        titleLabel.userInterfaceLayoutDirection = .leftToRight
        titleLabel.maximumNumberOfLines = 1
        titleLabel.lineBreakMode = .byTruncatingTail
        titleLabel.setContentHuggingPriority(.required, for: .horizontal)
        titleLabel.setContentCompressionResistancePriority(.required, for: .horizontal)

        let titleRowSpacer = NSView()
        titleRowSpacer.translatesAutoresizingMaskIntoConstraints = false
        titleRowSpacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
        titleRowSpacer.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        titleRow.addArrangedSubview(titleLabel)
        // To-do items are read-only from Classroom.
        titleRow.addArrangedSubview(titleRowSpacer)
        container.addArrangedSubview(titleRow)

        let filterRow = NSStackView()
        filterRow.translatesAutoresizingMaskIntoConstraints = false
        filterRow.userInterfaceLayoutDirection = .leftToRight
        filterRow.orientation = .horizontal
        filterRow.alignment = .centerY
        filterRow.spacing = 18
        filterRow.distribution = .fill

        let filterDropdown = makeSchedulePageFilterDropdown()
        schedulePageFilterDropdown = filterDropdown
        filterRow.addArrangedSubview(filterDropdown)
        filterRow.setCustomSpacing(20, after: filterDropdown)

        let (fromShell, fromPicker) = makeScheduleDatePicker(date: schedulePageFromDate)
        schedulePageFromDatePicker = fromPicker
        filterRow.addArrangedSubview(fromShell)
        filterRow.setCustomSpacing(16, after: fromShell)

        let (toShell, toPicker) = makeScheduleDatePicker(date: schedulePageToDate)
        schedulePageToDatePicker = toPicker
        filterRow.addArrangedSubview(toShell)
        NSLayoutConstraint.activate([
            fromShell.widthAnchor.constraint(equalTo: toShell.widthAnchor),
            fromShell.widthAnchor.constraint(greaterThanOrEqualToConstant: 152)
        ])

        let filterRowSpacer = NSView()
        filterRowSpacer.translatesAutoresizingMaskIntoConstraints = false
        filterRowSpacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
        filterRowSpacer.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        filterRow.addArrangedSubview(filterRowSpacer)

        let applyButton = makeSchedulePagePillButton(title: "Apply", action: #selector(schedulePageApplyDateRangePressed(_:)))
        filterRow.addArrangedSubview(applyButton)
        filterRow.setCustomSpacing(22, after: applyButton)
        let resetButton = makeSchedulePagePillButton(title: "Reset", action: #selector(schedulePageResetFiltersPressed(_:)))
        filterRow.addArrangedSubview(resetButton)
        filterRow.setCustomSpacing(22, after: resetButton)
        filterRow.addArrangedSubview(makeScheduleRefreshButton())

        container.addArrangedSubview(filterRow)
        NSLayoutConstraint.activate([
            titleRow.widthAnchor.constraint(equalTo: container.widthAnchor),
            filterRow.widthAnchor.constraint(equalTo: container.widthAnchor)
        ])
        refreshSchedulePageDateFilterUI()
        return container
    }

    private func makeSchedulePageFilterDropdown() -> NSPopUpButton {
        let button = HoverPopUpButton(frame: .zero, pullsDown: false)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.autoenablesItems = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = 8
        button.layer?.masksToBounds = true
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        button.layer?.borderColor = palette.inputBorder.cgColor
        button.layer?.borderWidth = 1
        button.font = typography.filterText
        button.contentTintColor = palette.textSecondary
        button.target = self
        button.action = #selector(schedulePageFilterDropdownChanged(_:))
        button.heightAnchor.constraint(equalToConstant: 34).isActive = true
        button.widthAnchor.constraint(equalToConstant: 228).isActive = true

        button.removeAllItems()
        button.addItems(withTitles: ["All", "Today", "This week", "This month", "Custom range"])
        button.selectItem(at: schedulePageFilter.rawValue)
        if let menu = button.menu {
            for (index, item) in menu.items.enumerated() {
                item.tag = index
            }
        }

        let baseColor = palette.inputBackground
        let baseBorder = palette.inputBorder
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverColor = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
        let hoverBorder = baseBorder.blended(withFraction: 0.16, of: hoverBlend) ?? baseBorder
        button.onHoverChanged = { [weak button] hovering in
            button?.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            button?.layer?.borderColor = (hovering ? hoverBorder : baseBorder).cgColor
        }
        button.onHoverChanged?(false)
        return button
    }

    /// Rounded shell matching `makeSchedulePageFilterDropdown` (34pt, 8pt corner, border + hover). Both pickers use the same field+stepper style inside the shell.
    private func makeScheduleDatePicker(date: Date) -> (NSView, NSDatePicker) {
        let shell = HoverSurfaceView()
        shell.translatesAutoresizingMaskIntoConstraints = false
        shell.wantsLayer = true
        shell.layer?.cornerRadius = 8
        shell.layer?.masksToBounds = true
        shell.layer?.borderWidth = 1

        let baseColor = palette.inputBackground
        let baseBorder = palette.inputBorder
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverBackground = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
        let hoverBorder = baseBorder.blended(withFraction: 0.16, of: hoverBlend) ?? baseBorder

        func applyShellIdleAppearance() {
            shell.layer?.backgroundColor = baseColor.cgColor
            shell.layer?.borderColor = baseBorder.cgColor
        }
        applyShellIdleAppearance()

        shell.onHoverChanged = { [weak shell] hovering in
            guard let shell else { return }
            shell.layer?.backgroundColor = (hovering ? hoverBackground : baseColor).cgColor
            shell.layer?.borderColor = (hovering ? hoverBorder : baseBorder).cgColor
        }

        let picker = NSDatePicker()
        picker.translatesAutoresizingMaskIntoConstraints = false
        picker.isBordered = false
        picker.drawsBackground = false
        picker.focusRingType = .none
        picker.datePickerStyle = .textFieldAndStepper
        picker.datePickerElements = [.yearMonthDay]
        picker.dateValue = date
        picker.font = typography.filterText
        picker.textColor = palette.textSecondary
        picker.setContentHuggingPriority(.defaultLow, for: .horizontal)
        picker.target = self
        picker.action = #selector(schedulePageDatePickerChanged(_:))

        shell.addSubview(picker)
        NSLayoutConstraint.activate([
            shell.heightAnchor.constraint(equalToConstant: 34),
            picker.leadingAnchor.constraint(equalTo: shell.leadingAnchor, constant: 8),
            picker.trailingAnchor.constraint(equalTo: shell.trailingAnchor, constant: -8),
            picker.centerYAnchor.constraint(equalTo: shell.centerYAnchor)
        ])

        return (shell, picker)
    }

    private func makeSchedulePagePillButton(title: String, action: Selector) -> NSButton {
        let button = makeSchedulePillButton(title: title)
        button.target = self
        button.action = action
        button.widthAnchor.constraint(equalToConstant: 100).isActive = true
        return button
    }

    private func makeSchedulePageCardsContainer() -> NSView {
        if let observer = schedulePageScrollObservation {
            NotificationCenter.default.removeObserver(observer)
        }
        schedulePageScrollObservation = nil

        let wrapper = NSView()
        wrapper.translatesAutoresizingMaskIntoConstraints = false
        wrapper.userInterfaceLayoutDirection = .leftToRight

        let scroll = NSScrollView()
        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.userInterfaceLayoutDirection = .leftToRight
        scroll.drawsBackground = false
        scroll.hasHorizontalScroller = false
        scroll.hasVerticalScroller = true
        scroll.autohidesScrollers = true
        scroll.borderType = .noBorder
        scroll.scrollerStyle = .overlay
        scroll.automaticallyAdjustsContentInsets = false
        let clip = TopAlignedClipView()
        clip.drawsBackground = false
        clip.postsBoundsChangedNotifications = true
        scroll.contentView = clip
        schedulePageCardsScrollView = scroll
        wrapper.addSubview(scroll)

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.userInterfaceLayoutDirection = .leftToRight
        stack.orientation = .vertical
        stack.spacing = schedulePageCardSpacing
        stack.alignment = .width
        schedulePageCardsStack = stack
        scroll.documentView = stack

        NSLayoutConstraint.activate([
            scroll.leadingAnchor.constraint(equalTo: wrapper.leadingAnchor),
            scroll.trailingAnchor.constraint(equalTo: wrapper.trailingAnchor),
            scroll.topAnchor.constraint(equalTo: wrapper.topAnchor),
            scroll.bottomAnchor.constraint(equalTo: wrapper.bottomAnchor),
            scroll.heightAnchor.constraint(greaterThanOrEqualToConstant: 420),

            stack.leadingAnchor.constraint(equalTo: scroll.contentView.leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: scroll.contentView.trailingAnchor),
            stack.topAnchor.constraint(equalTo: scroll.contentView.topAnchor),
            stack.widthAnchor.constraint(equalTo: scroll.contentView.widthAnchor)
        ])

        scroll.contentView.postsBoundsChangedNotifications = true
        schedulePageScrollObservation = NotificationCenter.default.addObserver(
            forName: NSView.boundsDidChangeNotification,
            object: scroll.contentView,
            queue: .main
        ) { [weak self] _ in
            self?.schedulePageScrolled()
        }

        renderSchedulePageCards()
        return wrapper
    }

    private func scheduleTopAuthRow() -> NSView {
        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.alignment = .centerY
        row.spacing = 10

        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false
        row.addArrangedSubview(spacer)
        spacer.setContentHuggingPriority(.defaultLow, for: .horizontal)

        let host = GoogleProfileAuthHostView()
        host.translatesAutoresizingMaskIntoConstraints = false
        let authButton = makeGoogleAuthButton()
        host.authButton = authButton
        scheduleGoogleAuthHostView = host
        scheduleGoogleAuthButton = authButton
        host.addSubview(authButton)
        NSLayoutConstraint.activate([
            authButton.centerXAnchor.constraint(equalTo: host.centerXAnchor),
            authButton.centerYAnchor.constraint(equalTo: host.centerYAnchor)
        ])
        let hostPadW = host.widthAnchor.constraint(equalTo: authButton.widthAnchor, constant: 0)
        let hostPadH = host.heightAnchor.constraint(equalTo: authButton.heightAnchor, constant: 0)
        hostPadW.isActive = true
        hostPadH.isActive = true
        scheduleGoogleAuthHostPadWidthConstraint = hostPadW
        scheduleGoogleAuthHostPadHeightConstraint = hostPadH
        updateGoogleAuthButtonTitle()
        row.addArrangedSubview(host)

        row.widthAnchor.constraint(greaterThanOrEqualToConstant: 780).isActive = true
        return row
    }

    private func makeScheduleFilterDropdown() -> NSPopUpButton {
        let button = HoverPopUpButton(frame: .zero, pullsDown: false)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.autoenablesItems = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = 8
        button.layer?.masksToBounds = true
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        button.layer?.borderColor = palette.inputBorder.cgColor
        button.layer?.borderWidth = 1
        button.font = typography.filterText
        button.contentTintColor = palette.textSecondary
        button.target = self
        button.action = #selector(scheduleFilterDropdownChanged(_:))
        button.heightAnchor.constraint(equalToConstant: 34).isActive = true
        button.widthAnchor.constraint(equalToConstant: 156).isActive = true

        button.removeAllItems()
        button.addItems(withTitles: ["All", "Today", "This week"])
        button.selectItem(at: scheduleFilter.rawValue)

        if let menu = button.menu {
            for (index, item) in menu.items.enumerated() {
                item.tag = index
            }
        }

        let baseColor = palette.inputBackground
        let baseBorder = palette.inputBorder
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverColor = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
        let hoverBorder = baseBorder.blended(withFraction: 0.16, of: hoverBlend) ?? baseBorder
        button.onHoverChanged = { [weak button] hovering in
            button?.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            button?.layer?.borderColor = (hovering ? hoverBorder : baseBorder).cgColor
        }
        button.onHoverChanged?(false)

        scheduleFilterDropdown = button
        return button
    }

    private func makeSchedulePillButton(title: String) -> NSButton {
        let button = NSButton(title: title, target: nil, action: nil)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = 8
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        button.layer?.borderColor = palette.inputBorder.cgColor
        button.layer?.borderWidth = 1
        button.font = typography.filterText
        button.contentTintColor = palette.textSecondary
        button.setButtonType(.momentaryChange)
        button.heightAnchor.constraint(equalToConstant: 34).isActive = true
        button.widthAnchor.constraint(greaterThanOrEqualToConstant: 132).isActive = true
        return button
    }

    private func makeGoogleAuthButton() -> NSButton {
        let button = HoverButton(title: "", target: self, action: #selector(scheduleConnectButtonPressed(_:)))
        button.translatesAutoresizingMaskIntoConstraints = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = 16
        button.layer?.borderWidth = 1
        button.font = NSFont.systemFont(ofSize: 14, weight: .semibold)
        button.imagePosition = .imageLeading
        button.alignment = .center
        button.imageHugsTitle = true
        button.lineBreakMode = .byTruncatingTail
        button.contentTintColor = palette.textPrimary
        button.imageScaling = .scaleNone
        button.layer?.masksToBounds = true
        let heightConstraint = button.heightAnchor.constraint(equalToConstant: 42)
        heightConstraint.isActive = true
        scheduleGoogleAuthButtonHeightConstraint = heightConstraint
        let widthConstraint = button.widthAnchor.constraint(equalToConstant: 248)
        widthConstraint.isActive = true
        scheduleGoogleAuthButtonWidthConstraint = widthConstraint
        button.onHoverChanged = { [weak self] hovering in
            self?.scheduleGoogleAuthHovering = hovering
            self?.scheduleGoogleAuthHostView?.setProfileHoverActive(hovering)
            self?.applyGoogleAuthButtonSurface()
        }
        button.onHoverChanged?(false)
        return button
    }

    private func makeScheduleRefreshButton() -> NSButton {
        let diameter: CGFloat = 30
        let button = HoverButton(title: "", target: self, action: #selector(scheduleReloadButtonPressed(_:)))
        button.translatesAutoresizingMaskIntoConstraints = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = diameter / 2
        button.layer?.masksToBounds = true
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        button.layer?.borderColor = palette.inputBorder.cgColor
        button.layer?.borderWidth = 1
        button.setButtonType(.momentaryChange)
        button.contentTintColor = palette.textSecondary
        button.image = NSImage(systemSymbolName: "arrow.clockwise", accessibilityDescription: "Refresh to-do")
        button.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 14, weight: .semibold)
        button.imagePosition = .imageOnly
        button.imageScaling = .scaleProportionallyDown
        button.focusRingType = .none
        button.heightAnchor.constraint(equalToConstant: diameter).isActive = true
        button.widthAnchor.constraint(equalToConstant: diameter).isActive = true
        let baseColor = palette.inputBackground
        let baseBorder = palette.inputBorder
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverColor = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
        let hoverBorder = baseBorder.blended(withFraction: 0.16, of: hoverBlend) ?? baseBorder
        button.onHoverChanged = { [weak button] hovering in
            button?.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            button?.layer?.borderColor = (hovering ? hoverBorder : baseBorder).cgColor
        }
        button.onHoverChanged?(false)
        return button
    }

    func scheduleCardsRow(todos: [ClassroomTodoItem]) -> NSView {
        let cardWidth: CGFloat = 240
        let cardsPerViewport: CGFloat = 3
        let viewportWidth = (cardWidth * cardsPerViewport) + (12 * (cardsPerViewport - 1))

        let wrapper = NSStackView()
        wrapper.translatesAutoresizingMaskIntoConstraints = false
        wrapper.orientation = .horizontal
        wrapper.alignment = .centerY
        wrapper.spacing = 10
        let leftButton = makeScheduleScrollButton(systemSymbol: "chevron.left", action: #selector(scheduleScrollLeftPressed(_:)))
        scheduleScrollLeftButton = leftButton
        wrapper.addArrangedSubview(leftButton)

        let scroll = NSScrollView()
        scheduleCardsScrollView = scroll
        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.drawsBackground = false
        scroll.hasHorizontalScroller = false
        scroll.hasVerticalScroller = false
        scroll.horizontalScrollElasticity = .allowed
        scroll.verticalScrollElasticity = .none
        scroll.autohidesScrollers = false
        scroll.borderType = .noBorder
        scroll.automaticallyAdjustsContentInsets = false
        scroll.heightAnchor.constraint(equalToConstant: 150).isActive = true
        scroll.widthAnchor.constraint(equalToConstant: viewportWidth).isActive = true

        let row = NSStackView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.spacing = 12
        row.alignment = .top
        row.distribution = .gravityAreas
        row.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        row.heightAnchor.constraint(equalToConstant: 150).isActive = true
        scheduleCardsStack = row

        scroll.documentView = row
        scroll.contentView.postsBoundsChangedNotifications = true

        // Pin top/leading/trailing only; avoid bottom == clip so the horizontal stack is not stretched vertically inside the clip (same as Schedule cards scroll).
        NSLayoutConstraint.activate([
            row.leadingAnchor.constraint(equalTo: scroll.contentView.leadingAnchor),
            row.trailingAnchor.constraint(greaterThanOrEqualTo: scroll.contentView.trailingAnchor),
            row.topAnchor.constraint(equalTo: scroll.contentView.topAnchor),
            row.heightAnchor.constraint(equalToConstant: 150)
        ])

        renderScheduleCards(into: row, todos: todos)
        wrapper.addArrangedSubview(scroll)
        let rightButton = makeScheduleScrollButton(systemSymbol: "chevron.right", action: #selector(scheduleScrollRightPressed(_:)))
        scheduleScrollRightButton = rightButton
        wrapper.addArrangedSubview(rightButton)
        scroll.setContentHuggingPriority(.defaultLow, for: .horizontal)
        scroll.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        wrapper.widthAnchor.constraint(greaterThanOrEqualToConstant: 780).isActive = true
        return wrapper
    }

    func scheduleCard(todo: ClassroomTodoItem, useFlexibleWidth: Bool = false, contentHeight: CGFloat = 150) -> NSView {
        let cardWidth: CGFloat = 240

        let card = roundedContainer(cornerRadius: 12, color: palette.sectionCard)
        styleSurface(card, borderColor: palette.inputBorder, borderWidth: 1, shadow: true)
        card.translatesAutoresizingMaskIntoConstraints = false
        card.heightAnchor.constraint(equalToConstant: contentHeight).isActive = true
        if useFlexibleWidth {
            card.setContentHuggingPriority(.defaultLow, for: .horizontal)
            card.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        } else {
            card.widthAnchor.constraint(equalToConstant: cardWidth).isActive = true
            card.setContentHuggingPriority(.required, for: .horizontal)
            card.setContentCompressionResistancePriority(.required, for: .horizontal)
        }

        let icon = roundedContainer(cornerRadius: 8, color: palette.meetingBadge)
        icon.translatesAutoresizingMaskIntoConstraints = false
        icon.widthAnchor.constraint(equalToConstant: 28).isActive = true
        icon.heightAnchor.constraint(equalToConstant: 28).isActive = true
        let iconView = NSImageView()
        iconView.translatesAutoresizingMaskIntoConstraints = false
        let iconSymbolName: String = {
            switch todo.workType {
            case .assignment:
                return "doc.text.fill"
            case .shortAnswerQuestion, .multipleChoiceQuestion:
                return "checkmark.seal.fill"
            case .unspecified:
                return "book.closed.fill"
            }
        }()
        iconView.image = NSImage(systemSymbolName: iconSymbolName, accessibilityDescription: "Classroom to-do")
        iconView.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 18, weight: .semibold)
        iconView.contentTintColor = .white
        icon.addSubview(iconView)
        NSLayoutConstraint.activate([
            iconView.centerXAnchor.constraint(equalTo: icon.centerXAnchor),
            iconView.centerYAnchor.constraint(equalTo: icon.centerYAnchor)
        ])

        let title = textLabel(todo.title, font: typography.cardTitle, color: palette.textPrimary)
        title.lineBreakMode = .byTruncatingTail
        title.maximumNumberOfLines = 1
        title.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        let subtitle = textLabel(todo.courseName, font: typography.cardSubtitle, color: palette.textPrimary)
        let time = textLabel(todoDueText(for: todo), font: typography.cardTime, color: palette.textSecondary)
        let duration = textLabel(todo.workType.displayName, font: NSFont.systemFont(ofSize: 11, weight: .medium), color: palette.textMuted)
        let dayChip = roundedContainer(cornerRadius: 7, color: palette.inputBackground)
        dayChip.translatesAutoresizingMaskIntoConstraints = false
        dayChip.layer?.borderWidth = 1
        dayChip.layer?.borderColor = palette.inputBorder.withAlphaComponent(0.8).cgColor
        let dayText = textLabel(todoDayText(for: todo), font: NSFont.systemFont(ofSize: 11, weight: .semibold), color: palette.textSecondary)
        dayText.translatesAutoresizingMaskIntoConstraints = false
        dayChip.addSubview(dayText)
        NSLayoutConstraint.activate([
            dayText.leadingAnchor.constraint(equalTo: dayChip.leadingAnchor, constant: 8),
            dayText.trailingAnchor.constraint(equalTo: dayChip.trailingAnchor, constant: -8),
            dayText.topAnchor.constraint(equalTo: dayChip.topAnchor, constant: 4),
            dayText.bottomAnchor.constraint(equalTo: dayChip.bottomAnchor, constant: -4)
        ])

        card.addSubview(icon)
        card.addSubview(dayChip)
        card.addSubview(title)
        card.addSubview(subtitle)
        card.addSubview(time)
        card.addSubview(duration)

        var titleConstraints: [NSLayoutConstraint] = [
            icon.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 10),
            icon.topAnchor.constraint(equalTo: card.topAnchor, constant: 10),

            dayChip.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -10),
            dayChip.centerYAnchor.constraint(equalTo: icon.centerYAnchor),

            title.leadingAnchor.constraint(equalTo: icon.trailingAnchor, constant: 6),
            title.centerYAnchor.constraint(equalTo: icon.centerYAnchor),
            title.trailingAnchor.constraint(lessThanOrEqualTo: dayChip.leadingAnchor, constant: -8)
        ]
        if !useFlexibleWidth {
            titleConstraints.append(title.widthAnchor.constraint(lessThanOrEqualToConstant: 130))
        }
        NSLayoutConstraint.activate(titleConstraints + [
            subtitle.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 10),
            subtitle.topAnchor.constraint(equalTo: icon.bottomAnchor, constant: 10),
            subtitle.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -10),

            time.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 10),
            time.topAnchor.constraint(equalTo: subtitle.bottomAnchor, constant: 5),
            time.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -10),

            duration.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 10),
            duration.topAnchor.constraint(equalTo: time.bottomAnchor, constant: 4),
            duration.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -10)
        ])

        let hit = HoverButton(title: "", target: self, action: #selector(scheduleCardButtonPressed(_:)))
        hit.translatesAutoresizingMaskIntoConstraints = false
        hit.isBordered = false
        hit.bezelStyle = .regularSquare
        if let url = todo.alternateLink {
            hit.identifier = NSUserInterfaceItemIdentifier(url.absoluteString)
        }
        hit.heightAnchor.constraint(equalToConstant: contentHeight).isActive = true
        if useFlexibleWidth {
            hit.setContentHuggingPriority(.defaultLow, for: .horizontal)
            hit.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        } else {
            hit.widthAnchor.constraint(equalToConstant: cardWidth).isActive = true
            hit.setContentHuggingPriority(.required, for: .horizontal)
            hit.setContentCompressionResistancePriority(.required, for: .horizontal)
        }
        hit.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: hit.leadingAnchor),
            card.trailingAnchor.constraint(equalTo: hit.trailingAnchor),
            card.topAnchor.constraint(equalTo: hit.topAnchor),
            card.bottomAnchor.constraint(equalTo: hit.bottomAnchor)
        ])
        hit.onHoverChanged = { [weak self] hovering in
            guard let self else { return }
            let base = self.palette.sectionCard
            let hoverBlend = self.darkModeEnabled ? NSColor.white : NSColor.black
            let hover = base.blended(withFraction: 0.10, of: hoverBlend) ?? base
            if self.storeKitCoordinator.hasPremiumAccess {
                card.layer?.backgroundColor = (hovering ? hover : base).cgColor
            } else {
                card.layer?.backgroundColor = base.cgColor
            }
        }
        hit.onHoverChanged?(false)

        if !storeKitCoordinator.hasPremiumAccess {
            let lockOverlay = NSVisualEffectView()
            lockOverlay.translatesAutoresizingMaskIntoConstraints = false
            lockOverlay.material = darkModeEnabled ? .hudWindow : .popover
            lockOverlay.blendingMode = .withinWindow
            lockOverlay.state = .active
            lockOverlay.wantsLayer = true
            lockOverlay.layer?.cornerRadius = 12
            lockOverlay.layer?.masksToBounds = true
            lockOverlay.layer?.backgroundColor = NSColor.black.withAlphaComponent(darkModeEnabled ? 0.28 : 0.12).cgColor

            let lockLabel = textLabel("Get Premium to see events", font: NSFont.systemFont(ofSize: 12, weight: .semibold), color: darkModeEnabled ? .white : .black)
            lockLabel.alignment = .center

            card.addSubview(lockOverlay)
            lockOverlay.addSubview(lockLabel)
            NSLayoutConstraint.activate([
                lockOverlay.leadingAnchor.constraint(equalTo: card.leadingAnchor),
                lockOverlay.trailingAnchor.constraint(equalTo: card.trailingAnchor),
                lockOverlay.topAnchor.constraint(equalTo: card.topAnchor),
                lockOverlay.bottomAnchor.constraint(equalTo: card.bottomAnchor),
                lockLabel.centerXAnchor.constraint(equalTo: lockOverlay.centerXAnchor),
                lockLabel.centerYAnchor.constraint(equalTo: lockOverlay.centerYAnchor),
                lockLabel.leadingAnchor.constraint(greaterThanOrEqualTo: lockOverlay.leadingAnchor, constant: 10),
                lockLabel.trailingAnchor.constraint(lessThanOrEqualTo: lockOverlay.trailingAnchor, constant: -10)
            ])
            hit.toolTip = "Premium required. Click to open paywall."
        }

        return hit
    }

    private func makeScheduleScrollButton(systemSymbol: String, action: Selector) -> NSButton {
        let button = HoverButton(title: "", target: self, action: action)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.isBordered = false
        button.bezelStyle = .regularSquare
        button.wantsLayer = true
        button.layer?.cornerRadius = 16
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        button.layer?.borderColor = palette.inputBorder.cgColor
        button.layer?.borderWidth = 1
        button.image = NSImage(systemSymbolName: systemSymbol, accessibilityDescription: "Scroll schedule")
        button.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 13, weight: .semibold)
        button.imagePosition = .imageOnly
        button.imageScaling = .scaleProportionallyDown
        button.contentTintColor = palette.textSecondary
        button.focusRingType = .none
        button.heightAnchor.constraint(equalToConstant: 32).isActive = true
        button.widthAnchor.constraint(equalToConstant: 32).isActive = true
        let baseColor = palette.inputBackground
        let baseBorder = palette.inputBorder
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverColor = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
        let hoverBorder = baseBorder.blended(withFraction: 0.16, of: hoverBlend) ?? baseBorder
        button.onHoverChanged = { [weak button] hovering in
            button?.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            button?.layer?.borderColor = (hovering ? hoverBorder : baseBorder).cgColor
        }
        button.onHoverChanged?(false)
        return button
    }
}

private extension PremiumPlan {
    var displayName: String {
        switch self {
        case .weekly: return "Weekly"
        case .monthly: return "Monthly"
        case .yearly: return "Yearly"
        case .lifetime: return "Lifetime"
        }
    }
}

extension ViewController: NSTextFieldDelegate {
    func control(_ control: NSControl, textView: NSTextView, doCommandBy commandSelector: Selector) -> Bool {
        if control === browseAddressField, commandSelector == #selector(NSResponder.insertNewline(_:)) {
            browseOpenAddressClicked(nil)
            return true
        }
        return false
    }
}

extension ViewController: NSWindowDelegate {
    func windowWillClose(_ notification: Notification) {
        guard let closingWindow = notification.object as? NSWindow else { return }
        if closingWindow === paywallWindow {
            paywallWindow = nil
            paywallUpgradeFlowEnabled = false
        }
    }
}

/// Default `NSClipView` uses a non-flipped coordinate system, so a document shorter than the visible area is anchored to the **bottom** of the clip, leaving a large gap above (e.g. Schedule empty state). Flipped coordinates match Auto Layout’s top-leading anchors and keep content top-aligned.
private final class TopAlignedClipView: NSClipView {
    override var isFlipped: Bool { true }
}

/// Wraps the Google auth control and draws a circular accent ring with a light pulse while the signed-in avatar is hovered.
private final class GoogleProfileAuthHostView: NSView {
    weak var authButton: NSButton? {
        didSet { needsLayout = true }
    }

    private let ringLayer = CAShapeLayer()
    private var avatarRingMode = false
    private static let ringLineWidth: CGFloat = 2.25

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        wantsLayer = true
        layer?.masksToBounds = false
        ringLayer.fillColor = nil
        ringLayer.strokeColor = NSColor.clear.cgColor
        ringLayer.lineWidth = Self.ringLineWidth
        ringLayer.lineCap = .round
        ringLayer.opacity = 0
        ringLayer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
        layer?.insertSublayer(ringLayer, at: 0)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        nil
    }

    func setAvatarRingMode(_ enabled: Bool) {
        avatarRingMode = enabled
        if enabled == false {
            ringLayer.removeAllAnimations()
            ringLayer.opacity = 0
            ringLayer.lineWidth = Self.ringLineWidth
        }
        needsLayout = true
    }

    func updateRingAppearance(isDark: Bool, accent: NSColor) {
        let stroke = isDark
            ? accent.blended(withFraction: 0.22, of: NSColor.white) ?? accent
            : accent
        CATransaction.begin()
        CATransaction.setDisableActions(true)
        ringLayer.strokeColor = stroke.withAlphaComponent(0.95).cgColor
        CATransaction.commit()
    }

    func setProfileHoverActive(_ active: Bool) {
        guard avatarRingMode else { return }
        ringLayer.removeAnimation(forKey: "pulse")
        if active {
            layoutRingPathIfNeeded()
            CATransaction.begin()
            CATransaction.setAnimationDuration(0.22)
            ringLayer.opacity = 1
            CATransaction.commit()
            let pulse = CABasicAnimation(keyPath: "lineWidth")
            pulse.fromValue = Self.ringLineWidth * 0.88
            pulse.toValue = Self.ringLineWidth * 1.45
            pulse.duration = 0.72
            pulse.autoreverses = true
            pulse.repeatCount = .infinity
            pulse.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
            ringLayer.add(pulse, forKey: "pulse")
        } else {
            CATransaction.begin()
            CATransaction.setAnimationDuration(0.18)
            ringLayer.opacity = 0
            CATransaction.commit()
            ringLayer.lineWidth = Self.ringLineWidth
        }
    }

    private func layoutRingPathIfNeeded() {
        guard avatarRingMode, let btn = authButton else { return }
        let f = btn.frame
        guard f.width > 1, f.height > 1 else { return }
        let center = CGPoint(x: f.midX, y: f.midY)
        let avatarR = min(f.width, f.height) / 2
        let gap: CGFloat = 3.5
        let ringRadius = avatarR + gap
        let d = ringRadius * 2
        CATransaction.begin()
        CATransaction.setDisableActions(true)
        ringLayer.bounds = CGRect(x: 0, y: 0, width: d, height: d)
        ringLayer.position = center
        ringLayer.path = CGPath(ellipseIn: CGRect(origin: .zero, size: CGSize(width: d, height: d)), transform: nil)
        CATransaction.commit()
    }

    override func layout() {
        super.layout()
        layoutRingPathIfNeeded()
    }
}

/// Ensures `NSClickGestureRecognizer` on the row receives clicks instead of child label/image views swallowing them.
private class RowHitTestView: NSView {
    override func hitTest(_ point: NSPoint) -> NSView? {
        return bounds.contains(point) ? self : nil
    }

    override func acceptsFirstMouse(for event: NSEvent?) -> Bool {
        true
    }
}

private final class HoverTrackingView: RowHitTestView {
    var onHoverChanged: ((Bool) -> Void)?
    var onClick: (() -> Void)?
    var showsHandCursor = true

    private var trackingAreaRef: NSTrackingArea?
    private var isHovering = false {
        didSet {
            guard isHovering != oldValue else { return }
            onHoverChanged?(isHovering)
        }
    }

    override func updateTrackingAreas() {
        super.updateTrackingAreas()
        if let trackingAreaRef {
            removeTrackingArea(trackingAreaRef)
        }
        let options: NSTrackingArea.Options = [
            .activeInKeyWindow,
            .inVisibleRect,
            .mouseEnteredAndExited
        ]
        let area = NSTrackingArea(rect: bounds, options: options, owner: self, userInfo: nil)
        addTrackingArea(area)
        trackingAreaRef = area
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        isHovering = true
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        isHovering = false
    }

    override func resetCursorRects() {
        super.resetCursorRects()
        guard showsHandCursor else { return }
        addCursorRect(bounds, cursor: .pointingHand)
    }

    override func mouseUp(with event: NSEvent) {
        super.mouseUp(with: event)
        guard event.type == .leftMouseUp else { return }
        onClick?()
    }
}

/// Hover tracking without overriding hit-testing; keeps controls like text fields interactive.
private final class HoverSurfaceView: NSView {
    var onHoverChanged: ((Bool) -> Void)?

    private var trackingAreaRef: NSTrackingArea?
    private var isHovering = false {
        didSet {
            guard isHovering != oldValue else { return }
            onHoverChanged?(isHovering)
        }
    }

    override func updateTrackingAreas() {
        super.updateTrackingAreas()
        if let trackingAreaRef {
            removeTrackingArea(trackingAreaRef)
        }
        let options: NSTrackingArea.Options = [
            .activeInKeyWindow,
            .inVisibleRect,
            .mouseEnteredAndExited
        ]
        let area = NSTrackingArea(rect: bounds, options: options, owner: self, userInfo: nil)
        addTrackingArea(area)
        trackingAreaRef = area
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        isHovering = true
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        isHovering = false
    }
}

private final class HoverButton: NSButton {
    var onHoverChanged: ((Bool) -> Void)?
    var showsHandCursor = true

    private var trackingAreaRef: NSTrackingArea?
    private var isHovering = false {
        didSet {
            guard isHovering != oldValue else { return }
            onHoverChanged?(isHovering)
        }
    }

    override func updateTrackingAreas() {
        super.updateTrackingAreas()
        if let trackingAreaRef {
            removeTrackingArea(trackingAreaRef)
        }
        let options: NSTrackingArea.Options = [
            .activeInKeyWindow,
            .inVisibleRect,
            .mouseEnteredAndExited
        ]
        let tracking = NSTrackingArea(rect: bounds, options: options, owner: self, userInfo: nil)
        addTrackingArea(tracking)
        trackingAreaRef = tracking
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        if showsHandCursor {
            NSCursor.pointingHand.set()
        }
        isHovering = true
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        isHovering = false
    }
}

private final class HoverPopUpButton: NSPopUpButton {
    var onHoverChanged: ((Bool) -> Void)?

    private var trackingAreaRef: NSTrackingArea?
    private var isHovering = false {
        didSet {
            guard isHovering != oldValue else { return }
            onHoverChanged?(isHovering)
        }
    }

    override func updateTrackingAreas() {
        super.updateTrackingAreas()
        if let trackingAreaRef {
            removeTrackingArea(trackingAreaRef)
        }
        let options: NSTrackingArea.Options = [
            .activeInKeyWindow,
            .inVisibleRect,
            .mouseEnteredAndExited
        ]
        let tracking = NSTrackingArea(rect: bounds, options: options, owner: self, userInfo: nil)
        addTrackingArea(tracking)
        trackingAreaRef = tracking
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        isHovering = true
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        isHovering = false
    }
}

private func circularNSImage(_ image: NSImage, diameter: CGFloat) -> NSImage {
    let size = NSSize(width: diameter, height: diameter)
    let result = NSImage(size: size)
    result.lockFocus()
    if let ctx = NSGraphicsContext.current {
        ctx.imageInterpolation = .high
    }
    let rect = NSRect(origin: .zero, size: size)
    let path = NSBezierPath(ovalIn: rect)
    path.addClip()
    let src = image.size.width > 0 && image.size.height > 0
        ? NSRect(origin: .zero, size: image.size)
        : NSRect(origin: .zero, size: size)
    image.draw(in: rect, from: src, operation: .copy, fraction: 1.0)
    result.unlockFocus()
    result.isTemplate = false
    return result
}

private final class GoogleAccountMenuViewController: NSViewController {
    private let palette: Palette
    private let darkModeEnabled: Bool
    private let displayName: String
    private let email: String
    private let avatar: NSImage?
    private let onSignOut: () -> Void

    init(
        palette: Palette,
        darkModeEnabled: Bool,
        displayName: String,
        email: String,
        avatar: NSImage?,
        onSignOut: @escaping () -> Void
    ) {
        self.palette = palette
        self.darkModeEnabled = darkModeEnabled
        self.displayName = displayName
        self.email = email
        self.avatar = avatar
        self.onSignOut = onSignOut
        super.init(nibName: nil, bundle: nil)
        view = makeContentView()
        view.appearance = NSAppearance(named: darkModeEnabled ? .darkAqua : .aqua)
        preferredContentSize = NSSize(width: 300, height: 158)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        nil
    }

    private func makeContentView() -> NSView {
        let root = NSView()
        root.translatesAutoresizingMaskIntoConstraints = false

        let card = NSView()
        card.translatesAutoresizingMaskIntoConstraints = false
        card.wantsLayer = true
        card.layer?.cornerRadius = 14
        card.layer?.backgroundColor = palette.sectionCard.cgColor
        card.layer?.borderColor = palette.inputBorder.cgColor
        card.layer?.borderWidth = 1
        card.layer?.shadowColor = NSColor.black.cgColor
        card.layer?.shadowOpacity = darkModeEnabled ? 0.5 : 0.2
        card.layer?.shadowOffset = CGSize(width: 0, height: 6)
        card.layer?.shadowRadius = 18
        card.layer?.masksToBounds = false

        root.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: root.leadingAnchor, constant: 8),
            card.trailingAnchor.constraint(equalTo: root.trailingAnchor, constant: -8),
            card.topAnchor.constraint(equalTo: root.topAnchor, constant: 8),
            card.bottomAnchor.constraint(equalTo: root.bottomAnchor, constant: -8),
            root.widthAnchor.constraint(equalToConstant: 300)
        ])

        let inner = NSStackView()
        inner.translatesAutoresizingMaskIntoConstraints = false
        inner.orientation = .vertical
        inner.spacing = 0
        inner.alignment = .leading
        card.addSubview(inner)

        NSLayoutConstraint.activate([
            inner.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 18),
            inner.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -18),
            inner.topAnchor.constraint(equalTo: card.topAnchor, constant: 18),
            inner.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -10)
        ])

        let headerRow = NSView()
        headerRow.translatesAutoresizingMaskIntoConstraints = false

        let avatarBox = NSView()
        avatarBox.translatesAutoresizingMaskIntoConstraints = false
        avatarBox.wantsLayer = true
        avatarBox.layer?.cornerRadius = 24
        avatarBox.layer?.masksToBounds = true
        avatarBox.layer?.borderColor = palette.inputBorder.cgColor
        avatarBox.layer?.borderWidth = 1

        let avatarView = NSImageView()
        avatarView.translatesAutoresizingMaskIntoConstraints = false
        avatarView.imageScaling = .scaleAxesIndependently
        avatarView.image = resolvedAvatarImage()

        avatarBox.addSubview(avatarView)
        NSLayoutConstraint.activate([
            avatarBox.widthAnchor.constraint(equalToConstant: 48),
            avatarBox.heightAnchor.constraint(equalToConstant: 48),
            avatarView.leadingAnchor.constraint(equalTo: avatarBox.leadingAnchor),
            avatarView.trailingAnchor.constraint(equalTo: avatarBox.trailingAnchor),
            avatarView.topAnchor.constraint(equalTo: avatarBox.topAnchor),
            avatarView.bottomAnchor.constraint(equalTo: avatarBox.bottomAnchor)
        ])

        let textColumn = NSStackView()
        textColumn.translatesAutoresizingMaskIntoConstraints = false
        textColumn.orientation = .vertical
        textColumn.spacing = 3
        textColumn.alignment = .leading

        let nameField = NSTextField(labelWithString: displayName)
        nameField.translatesAutoresizingMaskIntoConstraints = false
        nameField.font = NSFont.systemFont(ofSize: 15, weight: .semibold)
        nameField.textColor = palette.textPrimary
        nameField.lineBreakMode = .byTruncatingTail
        nameField.maximumNumberOfLines = 1
        nameField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        let emailField = NSTextField(labelWithString: email)
        emailField.translatesAutoresizingMaskIntoConstraints = false
        emailField.font = NSFont.systemFont(ofSize: 12, weight: .regular)
        emailField.textColor = palette.textTertiary
        emailField.lineBreakMode = .byTruncatingTail
        emailField.maximumNumberOfLines = 1
        emailField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        textColumn.addArrangedSubview(nameField)
        textColumn.addArrangedSubview(emailField)

        headerRow.addSubview(avatarBox)
        headerRow.addSubview(textColumn)

        NSLayoutConstraint.activate([
            avatarBox.leadingAnchor.constraint(equalTo: headerRow.leadingAnchor),
            avatarBox.topAnchor.constraint(equalTo: headerRow.topAnchor),
            avatarBox.bottomAnchor.constraint(lessThanOrEqualTo: headerRow.bottomAnchor),

            textColumn.leadingAnchor.constraint(equalTo: avatarBox.trailingAnchor, constant: 14),
            textColumn.trailingAnchor.constraint(equalTo: headerRow.trailingAnchor),
            textColumn.centerYAnchor.constraint(equalTo: avatarBox.centerYAnchor),
            textColumn.topAnchor.constraint(greaterThanOrEqualTo: headerRow.topAnchor),
            textColumn.bottomAnchor.constraint(lessThanOrEqualTo: headerRow.bottomAnchor)
        ])

        inner.addArrangedSubview(headerRow)
        headerRow.widthAnchor.constraint(equalTo: inner.widthAnchor).isActive = true

        inner.setCustomSpacing(14, after: headerRow)

        let separator = NSView()
        separator.translatesAutoresizingMaskIntoConstraints = false
        separator.wantsLayer = true
        separator.layer?.backgroundColor = palette.separator.cgColor
        separator.heightAnchor.constraint(equalToConstant: 1).isActive = true
        inner.addArrangedSubview(separator)
        separator.widthAnchor.constraint(equalTo: inner.widthAnchor).isActive = true

        inner.setCustomSpacing(6, after: separator)

        let signOutRow = HoverTrackingView()
        signOutRow.translatesAutoresizingMaskIntoConstraints = false
        signOutRow.heightAnchor.constraint(equalToConstant: 44).isActive = true
        signOutRow.wantsLayer = true
        signOutRow.layer?.cornerRadius = 10

        let signOutIcon = NSImageView()
        signOutIcon.translatesAutoresizingMaskIntoConstraints = false
        signOutIcon.imageScaling = .scaleProportionallyDown
        if let sym = NSImage(systemSymbolName: "rectangle.portrait.and.arrow.right", accessibilityDescription: nil) {
            signOutIcon.image = sym
            signOutIcon.contentTintColor = palette.textSecondary
            signOutIcon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 14, weight: .medium)
        }

        let signOutLabel = NSTextField(labelWithString: "Log out")
        signOutLabel.translatesAutoresizingMaskIntoConstraints = false
        signOutLabel.font = NSFont.systemFont(ofSize: 14, weight: .medium)
        signOutLabel.textColor = palette.textPrimary

        signOutRow.addSubview(signOutIcon)
        signOutRow.addSubview(signOutLabel)

        NSLayoutConstraint.activate([
            signOutIcon.leadingAnchor.constraint(equalTo: signOutRow.leadingAnchor, constant: 10),
            signOutIcon.centerYAnchor.constraint(equalTo: signOutRow.centerYAnchor),
            signOutIcon.widthAnchor.constraint(equalToConstant: 20),
            signOutIcon.heightAnchor.constraint(equalToConstant: 20),

            signOutLabel.leadingAnchor.constraint(equalTo: signOutIcon.trailingAnchor, constant: 10),
            signOutLabel.centerYAnchor.constraint(equalTo: signOutRow.centerYAnchor),
            signOutLabel.trailingAnchor.constraint(lessThanOrEqualTo: signOutRow.trailingAnchor, constant: -10)
        ])

        let signOutClick = NSClickGestureRecognizer(target: self, action: #selector(signOutClicked))
        signOutRow.addGestureRecognizer(signOutClick)

        signOutRow.onHoverChanged = { [weak self] hovering in
            guard let self else { return }
            signOutRow.layer?.backgroundColor = (hovering ? self.palette.inputBackground : NSColor.clear).cgColor
        }
        signOutRow.onHoverChanged?(false)

        inner.addArrangedSubview(signOutRow)
        signOutRow.widthAnchor.constraint(equalTo: inner.widthAnchor).isActive = true

        return root
    }

    private func resolvedAvatarImage() -> NSImage {
        if let a = avatar {
            return circularNSImage(a, diameter: 48)
        }
        return initialLetterAvatar()
    }

    private func initialLetterAvatar() -> NSImage {
        let d: CGFloat = 48
        let letter = displayName.trimmingCharacters(in: .whitespacesAndNewlines).first.map { String($0).uppercased() } ?? "?"
        let img = NSImage(size: NSSize(width: d, height: d))
        img.lockFocus()
        palette.primaryBlue.setFill()
        NSBezierPath(ovalIn: NSRect(x: 0, y: 0, width: d, height: d)).fill()
        let attrs: [NSAttributedString.Key: Any] = [
            .font: NSFont.systemFont(ofSize: 20, weight: .semibold),
            .foregroundColor: NSColor.white
        ]
        let sz = (letter as NSString).size(withAttributes: attrs)
        let origin = NSPoint(x: (d - sz.width) / 2, y: (d - sz.height) / 2)
        (letter as NSString).draw(at: origin, withAttributes: attrs)
        img.unlockFocus()
        img.isTemplate = false
        return img
    }

    @objc private func signOutClicked() {
        onSignOut()
    }
}

private final class SettingsMenuViewController: NSViewController {
    private let palette: Palette
    private let typography: Typography
    private let onToggleDarkMode: (Bool) -> Void
    private let onAction: (SettingsAction, NSView?, NSPoint?) -> Void

    private var darkToggle: NSSwitch?

    init(
        palette: Palette,
        typography: Typography,
        darkModeEnabled: Bool,
        showRateUsInSettings: Bool,
        showUpgradeInSettings: Bool,
        onToggleDarkMode: @escaping (Bool) -> Void,
        onAction: @escaping (SettingsAction, NSView?, NSPoint?) -> Void
    ) {
        self.palette = palette
        self.typography = typography
        self.onToggleDarkMode = onToggleDarkMode
        self.onAction = onAction
        super.init(nibName: nil, bundle: nil)
        self.view = makeView(
            darkModeEnabled: darkModeEnabled,
            showRateUsInSettings: showRateUsInSettings,
            showUpgradeInSettings: showUpgradeInSettings
        )
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        nil
    }

    func setDarkModeEnabled(_ enabled: Bool) {
        darkToggle?.state = enabled ? .on : .off
    }

    private func makeView(
        darkModeEnabled: Bool,
        showRateUsInSettings: Bool,
        showUpgradeInSettings: Bool
    ) -> NSView {
        let root = NSView()
        root.translatesAutoresizingMaskIntoConstraints = false

        let card = roundedCard()
        root.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: root.leadingAnchor),
            card.trailingAnchor.constraint(equalTo: root.trailingAnchor),
            card.topAnchor.constraint(equalTo: root.topAnchor),
            card.bottomAnchor.constraint(equalTo: root.bottomAnchor),
            root.widthAnchor.constraint(equalToConstant: 260)
        ])

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.orientation = .vertical
        stack.spacing = 6
        stack.alignment = .leading
        card.addSubview(stack)

        NSLayoutConstraint.activate([
            stack.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 14),
            stack.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -14),
            stack.topAnchor.constraint(equalTo: card.topAnchor, constant: 14),
            stack.bottomAnchor.constraint(lessThanOrEqualTo: card.bottomAnchor, constant: -14)
        ])

        stack.addArrangedSubview(settingsDarkModeRow(enabled: darkModeEnabled))
        if showRateUsInSettings {
            stack.addArrangedSubview(settingsActionRow(icon: "★", title: "Rate Us", action: .rateUs))
        }
        stack.addArrangedSubview(settingsActionRow(icon: "🔒", title: "Privacy Policy", action: .privacyPolicy))
        stack.addArrangedSubview(settingsActionRow(icon: "💬", title: "Support", action: .support))
        stack.addArrangedSubview(settingsActionRow(icon: "📄", title: "Terms of Services", action: .termsOfServices))
        stack.addArrangedSubview(settingsActionRow(icon: "⤴︎", title: "Share App", action: .shareApp))
        if showUpgradeInSettings {
            stack.addArrangedSubview(settingsActionRow(icon: "⬆︎", title: "Upgrade", action: .upgrade))
        }

        for v in stack.arrangedSubviews {
            v.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        }

        return root
    }

    private func roundedCard() -> NSView {
        let view = NSView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.wantsLayer = true
        view.layer?.cornerRadius = 12
        view.layer?.backgroundColor = palette.sectionCard.cgColor
        view.layer?.borderColor = palette.inputBorder.cgColor
        view.layer?.borderWidth = 1
        view.layer?.shadowColor = NSColor.black.cgColor
        view.layer?.shadowOpacity = 0.28
        view.layer?.shadowOffset = CGSize(width: 0, height: -1)
        view.layer?.shadowRadius = 10
        return view
    }

    private func settingsDarkModeRow(enabled: Bool) -> NSView {
        let row = NSView()
        row.translatesAutoresizingMaskIntoConstraints = false
        row.heightAnchor.constraint(equalToConstant: 44).isActive = true
        row.wantsLayer = true
        row.layer?.cornerRadius = 10

        let icon = NSTextField(labelWithString: "◐")
        icon.translatesAutoresizingMaskIntoConstraints = false
        icon.font = NSFont.systemFont(ofSize: 18, weight: .medium)
        icon.textColor = palette.textPrimary

        let title = NSTextField(labelWithString: "Dark Mode")
        title.translatesAutoresizingMaskIntoConstraints = false
        title.font = NSFont.systemFont(ofSize: 16, weight: .semibold)
        title.textColor = palette.textPrimary

        let toggle = NSSwitch()
        toggle.translatesAutoresizingMaskIntoConstraints = false
        toggle.state = enabled ? .on : .off
        toggle.target = self
        toggle.action = #selector(darkModeToggled(_:))
        darkToggle = toggle

        row.addSubview(icon)
        row.addSubview(title)
        row.addSubview(toggle)
        row.layer?.backgroundColor = NSColor.clear.cgColor

        NSLayoutConstraint.activate([
            icon.leadingAnchor.constraint(equalTo: row.leadingAnchor, constant: 4),
            icon.centerYAnchor.constraint(equalTo: row.centerYAnchor),

            title.leadingAnchor.constraint(equalTo: icon.trailingAnchor, constant: 10),
            title.centerYAnchor.constraint(equalTo: row.centerYAnchor),

            toggle.trailingAnchor.constraint(equalTo: row.trailingAnchor, constant: -2),
            toggle.centerYAnchor.constraint(equalTo: row.centerYAnchor)
        ])

        return row
    }

    private func settingsActionRow(icon: String, title: String, action: SettingsAction) -> NSView {
        let row = HoverButton(title: "", target: self, action: #selector(settingsActionButtonPressed(_:)))
        row.tag = action.rawValue
        row.isBordered = false
        row.translatesAutoresizingMaskIntoConstraints = false
        row.heightAnchor.constraint(equalToConstant: 42).isActive = true
        row.wantsLayer = true
        row.layer?.cornerRadius = 10
        row.layer?.backgroundColor = NSColor.clear.cgColor

        let iconLabel = NSTextField(labelWithString: icon)
        iconLabel.translatesAutoresizingMaskIntoConstraints = false
        iconLabel.font = NSFont.systemFont(ofSize: 18, weight: .medium)
        iconLabel.textColor = palette.textPrimary

        let titleLabel = NSTextField(labelWithString: title)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        titleLabel.font = NSFont.systemFont(ofSize: 16, weight: .semibold)
        titleLabel.textColor = palette.textPrimary

        row.addSubview(iconLabel)
        row.addSubview(titleLabel)

        NSLayoutConstraint.activate([
            iconLabel.leadingAnchor.constraint(equalTo: row.leadingAnchor, constant: 4),
            iconLabel.centerYAnchor.constraint(equalTo: row.centerYAnchor),
            titleLabel.leadingAnchor.constraint(equalTo: iconLabel.trailingAnchor, constant: 10),
            titleLabel.centerYAnchor.constraint(equalTo: row.centerYAnchor)
        ])

        row.onHoverChanged = { hovering in
            row.layer?.backgroundColor = (hovering ? self.palette.inputBackground : NSColor.clear).cgColor
        }
        row.onHoverChanged?(false)

        return row
    }

    @objc private func darkModeToggled(_ sender: NSSwitch) {
        onToggleDarkMode(sender.state == .on)
    }

    @objc private func settingsActionButtonPressed(_ sender: NSButton) {
        guard let action = SettingsAction(rawValue: sender.tag) else { return }
        let clickPoint: NSPoint?
        if let event = NSApp.currentEvent {
            let pointInWindow = event.locationInWindow
            clickPoint = sender.convert(pointInWindow, from: nil)
        } else {
            clickPoint = nil
        }
        onAction(action, sender, clickPoint)
    }

}

private extension ViewController {
    func roundedContainer(cornerRadius: CGFloat, color: NSColor) -> NSView {
        let view = NSView()
        view.wantsLayer = true
        view.layer?.backgroundColor = color.cgColor
        view.layer?.cornerRadius = cornerRadius
        return view
    }

    func styleSurface(_ view: NSView, borderColor: NSColor, borderWidth: CGFloat, shadow: Bool) {
        view.layer?.borderColor = borderColor.cgColor
        view.layer?.borderWidth = borderWidth
        if shadow {
            view.layer?.shadowColor = NSColor.black.cgColor
            view.layer?.shadowOpacity = 0.18
            view.layer?.shadowOffset = CGSize(width: 0, height: -1)
            view.layer?.shadowRadius = 5
        }
    }

    func textLabel(_ text: String, font: NSFont, color: NSColor) -> NSTextField {
        let label = NSTextField(labelWithString: text)
        label.translatesAutoresizingMaskIntoConstraints = false
        label.textColor = color
        label.font = font
        return label
    }

    func iconLabel(_ text: String, size: CGFloat) -> NSTextField {
        let label = NSTextField(labelWithString: text)
        label.translatesAutoresizingMaskIntoConstraints = false
        label.font = NSFont.systemFont(ofSize: size)
        return label
    }

    func sidebarSectionTitle(_ text: String) -> NSTextField {
        let field = textLabel(text, font: typography.sidebarSection, color: palette.textMuted)
        field.alignment = .left
        return field
    }

    func sidebarItem(_ text: String, icon: String, page: SidebarPage, logoImageName: String? = nil, systemSymbolName: String? = nil, logoIconWidth: CGFloat = 18, logoHeightMultiplier: CGFloat = 1, logoTemplate: Bool = true, showsDisclosure: Bool = false) -> NSView {
        let item = HoverButton(title: "", target: self, action: #selector(sidebarButtonClicked(_:)))
        item.tag = page.rawValue
        item.isBordered = false
        item.wantsLayer = true
        item.layer?.cornerRadius = 10
        item.layer?.backgroundColor = NSColor.clear.cgColor
        item.translatesAutoresizingMaskIntoConstraints = false
        item.heightAnchor.constraint(equalToConstant: 36).isActive = true
        item.layer?.borderWidth = 0
        sidebarPageByView[ObjectIdentifier(item)] = page

        let leadingView: NSView
        if let name = logoImageName, let logo = NSImage(named: name) {
            logo.isTemplate = true
            let imageView = NSImageView(image: logo)
            imageView.translatesAutoresizingMaskIntoConstraints = false
            imageView.imageScaling = .scaleProportionallyDown
            imageView.imageAlignment = .alignCenter
            imageView.isEditable = false
            leadingView = imageView
        } else if let symbolName = systemSymbolName, let symbol = NSImage(systemSymbolName: symbolName, accessibilityDescription: text) {
            symbol.isTemplate = true
            let imageView = NSImageView(image: symbol)
            imageView.translatesAutoresizingMaskIntoConstraints = false
            imageView.imageScaling = .scaleProportionallyDown
            imageView.imageAlignment = .alignCenter
            imageView.isEditable = false
            leadingView = imageView
        } else {
            leadingView = textLabel(icon, font: typography.sidebarIcon, color: palette.textSecondary)
        }

        let titleLabel = textLabel(text, font: typography.sidebarItem, color: palette.textSecondary)
        titleLabel.alignment = .left

        item.addSubview(leadingView)
        item.addSubview(titleLabel)

        var constraints: [NSLayoutConstraint] = [
            leadingView.leadingAnchor.constraint(equalTo: item.leadingAnchor, constant: 12),
            leadingView.centerYAnchor.constraint(equalTo: item.centerYAnchor),
            titleLabel.leadingAnchor.constraint(equalTo: leadingView.trailingAnchor, constant: 8),
            titleLabel.centerYAnchor.constraint(equalTo: item.centerYAnchor)
        ]

        if showsDisclosure {
            let chevron = textLabel("›", font: NSFont.systemFont(ofSize: 22, weight: .semibold), color: palette.textSecondary)
            chevron.translatesAutoresizingMaskIntoConstraints = false
            chevron.alignment = .right
            item.addSubview(chevron)
            constraints.append(contentsOf: [
                chevron.trailingAnchor.constraint(equalTo: item.trailingAnchor, constant: -10),
                chevron.centerYAnchor.constraint(equalTo: item.centerYAnchor),
                titleLabel.trailingAnchor.constraint(lessThanOrEqualTo: chevron.leadingAnchor, constant: -8)
            ])
        } else {
            constraints.append(titleLabel.trailingAnchor.constraint(lessThanOrEqualTo: item.trailingAnchor, constant: -10))
        }

        if logoImageName != nil || systemSymbolName != nil {
            let h = logoIconWidth * logoHeightMultiplier
            constraints.append(contentsOf: [
                leadingView.widthAnchor.constraint(equalToConstant: logoIconWidth),
                leadingView.heightAnchor.constraint(equalToConstant: h)
            ])
        }
        NSLayoutConstraint.activate(constraints)

        applySidebarRowStyle(item, page: page, logoTemplate: logoTemplate)
        item.onHoverChanged = { [weak self, weak item] hovering in
            guard let self, let item else { return }
            self.applySidebarRowStyle(item, page: page, logoTemplate: logoTemplate, hovering: hovering)
        }

        return item
    }

    func applySidebarRowStyle(_ item: NSView, page: SidebarPage, logoTemplate: Bool, hovering: Bool = false) {
        let selected = (page == selectedSidebarPage)
        let neutralHover = darkModeEnabled ? NSColor(calibratedWhite: 1, alpha: 0.07) : NSColor(calibratedWhite: 0, alpha: 0.08)
        let greenHover = palette.primaryBlue.withAlphaComponent(darkModeEnabled ? 0.22 : 0.14)
        let hoverColor = greenHover.blended(withFraction: 0.45, of: neutralHover) ?? greenHover
        item.layer?.backgroundColor = (selected ? palette.primaryBlue : (hovering ? hoverColor : NSColor.clear)).cgColor
        let tint = selected ? NSColor.white : palette.textSecondary
        let sidebarIconTint = darkModeEnabled ? tint : NSColor.black
        guard item.subviews.count >= 2 else { return }
        let leading = item.subviews[0]
        let title = item.subviews.first { $0 is NSTextField } as? NSTextField
        title?.textColor = tint
        // Optional disclosure chevron (if present) is the last text field.
        if let chevron = item.subviews.last as? NSTextField, chevron !== title {
            chevron.textColor = sidebarIconTint
        }
        if let imageView = leading as? NSImageView {
            if logoTemplate {
                imageView.contentTintColor = sidebarIconTint
            }
        } else if let iconField = leading as? NSTextField {
            iconField.textColor = sidebarIconTint
        }
    }

    func actionButton(title: String, color: NSColor, textColor: NSColor, width: CGFloat) -> NSView {
        let button = HoverTrackingView()
        button.wantsLayer = true
        button.layer?.cornerRadius = 9
        button.layer?.backgroundColor = color.cgColor
        button.translatesAutoresizingMaskIntoConstraints = false
        button.widthAnchor.constraint(equalToConstant: width).isActive = true
        button.heightAnchor.constraint(equalToConstant: 36).isActive = true
        styleSurface(button, borderColor: title == "Cancel" ? palette.inputBorder : palette.primaryBlueBorder, borderWidth: 1, shadow: false)
        if title == "Cancel" {
            button.layer?.backgroundColor = palette.cancelButton.cgColor
        }

        let label = textLabel(title, font: typography.buttonText, color: textColor)
        button.addSubview(label)
        NSLayoutConstraint.activate([
            label.centerXAnchor.constraint(equalTo: button.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: button.centerYAnchor)
        ])

        let baseColor = (title == "Cancel") ? palette.cancelButton : color
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverColor = baseColor.blended(withFraction: 0.12, of: hoverBlend) ?? baseColor
        button.onHoverChanged = { hovering in
            button.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
        }
        button.onHoverChanged?(false)

        return button
    }

    func iconRoundButton(systemSymbol: String, size: CGFloat, iconPointSize: CGFloat = 16, onClick: (() -> Void)? = nil) -> NSView {
        let button = HoverTrackingView()
        button.wantsLayer = true
        button.layer?.cornerRadius = size / 2
        button.layer?.backgroundColor = palette.inputBackground.cgColor
        button.translatesAutoresizingMaskIntoConstraints = false
        button.widthAnchor.constraint(equalToConstant: size).isActive = true
        button.heightAnchor.constraint(equalToConstant: size).isActive = true
        styleSurface(button, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

        let symbolConfig = NSImage.SymbolConfiguration(pointSize: iconPointSize, weight: .semibold)
        let iconView = NSImageView()
        iconView.translatesAutoresizingMaskIntoConstraints = false
        iconView.image = NSImage(systemSymbolName: systemSymbol, accessibilityDescription: "Refresh")
        iconView.symbolConfiguration = symbolConfig
        iconView.contentTintColor = palette.textSecondary
        button.addSubview(iconView)
        NSLayoutConstraint.activate([
            iconView.centerXAnchor.constraint(equalTo: button.centerXAnchor),
            iconView.centerYAnchor.constraint(equalTo: button.centerYAnchor)
        ])

        let baseColor = palette.inputBackground
        let hoverBlend = darkModeEnabled ? NSColor.white : NSColor.black
        let hoverColor = baseColor.blended(withFraction: 0.10, of: hoverBlend) ?? baseColor
        button.onHoverChanged = { hovering in
            button.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
        }
        button.onHoverChanged?(false)
        button.onClick = onClick

        return button
    }
}

private final class EnrolledClassDetailsViewController: NSViewController {
    private let details: ClassroomClassDetails
    private let palette: Palette
    private let typography: Typography
    private let defaultAuthorName: String
    private let defaultAuthorAvatar: NSImage?
    private let onOpenClass: () -> Void
    private let onOpenURL: (URL) -> Void
    private let onDownloadAttachment: (ClassroomAttachment) -> Void
    private var attachmentByButton = [ObjectIdentifier: ClassroomAttachment]()

    init(details: ClassroomClassDetails,
         palette: Palette,
         typography: Typography,
         defaultAuthorName: String,
         defaultAuthorAvatar: NSImage?,
         onOpenClass: @escaping () -> Void,
         onOpenURL: @escaping (URL) -> Void,
         onDownloadAttachment: @escaping (ClassroomAttachment) -> Void) {
        self.details = details
        self.palette = palette
        self.typography = typography
        self.defaultAuthorName = defaultAuthorName
        self.defaultAuthorAvatar = defaultAuthorAvatar
        self.onOpenClass = onOpenClass
        self.onOpenURL = onOpenURL
        self.onDownloadAttachment = onDownloadAttachment
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) { nil }

    override func loadView() {
        let root = NSView()
        root.translatesAutoresizingMaskIntoConstraints = false
        root.wantsLayer = true
        root.layer?.backgroundColor = palette.sectionCard.cgColor
        root.layer?.cornerRadius = 12
        root.layer?.borderWidth = 1
        root.layer?.borderColor = palette.inputBorder.cgColor

        let contentScroll = NSScrollView()
        contentScroll.translatesAutoresizingMaskIntoConstraints = false
        contentScroll.drawsBackground = false
        contentScroll.hasVerticalScroller = true
        contentScroll.hasHorizontalScroller = false
        contentScroll.autohidesScrollers = true
        contentScroll.borderType = .noBorder
        contentScroll.scrollerStyle = .overlay
        let clip = TopAlignedClipView()
        clip.drawsBackground = false
        contentScroll.contentView = clip
        root.addSubview(contentScroll)

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.orientation = .vertical
        stack.alignment = .width
        stack.spacing = 16
        contentScroll.documentView = stack

        let pageHeader = makePageHeader()
        stack.addArrangedSubview(pageHeader)

        if details.announcements.isEmpty, details.coursework.isEmpty {
            let empty = makeEmptyState()
            stack.addArrangedSubview(empty)
            empty.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        } else {
            for item in details.announcements {
                let card = makeAnnouncementCard(item)
                stack.addArrangedSubview(card)
                card.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            }
            for item in details.coursework {
                let card = makeCourseworkCard(item)
                stack.addArrangedSubview(card)
                card.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            }
        }

        NSLayoutConstraint.activate([
            root.widthAnchor.constraint(equalToConstant: 520),
            root.heightAnchor.constraint(equalToConstant: 560),
            contentScroll.leadingAnchor.constraint(equalTo: root.leadingAnchor, constant: 12),
            contentScroll.trailingAnchor.constraint(equalTo: root.trailingAnchor, constant: -12),
            contentScroll.topAnchor.constraint(equalTo: root.topAnchor, constant: 12),
            contentScroll.bottomAnchor.constraint(equalTo: root.bottomAnchor, constant: -12),
            stack.leadingAnchor.constraint(equalTo: contentScroll.contentView.leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: contentScroll.contentView.trailingAnchor),
            stack.topAnchor.constraint(equalTo: contentScroll.contentView.topAnchor),
            stack.widthAnchor.constraint(equalTo: contentScroll.contentView.widthAnchor),
            pageHeader.widthAnchor.constraint(equalTo: stack.widthAnchor)
        ])

        view = root
    }

    @objc private func openClassPressed(_ sender: NSButton) {
        onOpenClass()
    }

    @objc private func openLinkPressed(_ sender: NSButton) {
        guard let raw = sender.identifier?.rawValue, let url = URL(string: raw) else { return }
        onOpenURL(url)
    }

    @objc private func downloadPressed(_ sender: NSButton) {
        guard let attachment = attachmentByButton[ObjectIdentifier(sender)] else { return }
        onDownloadAttachment(attachment)
    }

    private func makePageHeader() -> NSView {
        let title = NSTextField(labelWithString: details.courseName)
        title.font = NSFont.systemFont(ofSize: 18, weight: .bold)
        title.textColor = palette.textPrimary
        title.maximumNumberOfLines = 2
        title.lineBreakMode = .byWordWrapping

        let subtitle = NSTextField(labelWithString: "Class stream")
        subtitle.font = NSFont.systemFont(ofSize: 12, weight: .medium)
        subtitle.textColor = palette.textMuted

        let openClassButton = HoverButton(title: "", target: self, action: #selector(openClassPressed(_:)))
        openClassButton.translatesAutoresizingMaskIntoConstraints = false
        openClassButton.bezelStyle = .regularSquare
        openClassButton.image = NSImage(systemSymbolName: "arrow.up.right.square", accessibilityDescription: "Open in Classroom")
        openClassButton.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 14, weight: .semibold)
        openClassButton.imagePosition = .imageOnly
        openClassButton.contentTintColor = palette.textPrimary
        openClassButton.setAccessibilityLabel("Open in Classroom")
        openClassButton.toolTip = "Open in Classroom"
        openClassButton.wantsLayer = true
        openClassButton.layer?.cornerRadius = 8
        openClassButton.layer?.borderWidth = 1
        openClassButton.widthAnchor.constraint(equalToConstant: 34).isActive = true
        openClassButton.heightAnchor.constraint(equalToConstant: 34).isActive = true
        let buttonBase = palette.inputBackground
        let buttonHover = buttonBase.blended(withFraction: 0.14, of: palette.primaryBlue) ?? buttonBase
        openClassButton.layer?.backgroundColor = buttonBase.cgColor
        openClassButton.layer?.borderColor = palette.inputBorder.cgColor
        openClassButton.onHoverChanged = { [weak openClassButton] hovering in
            guard let openClassButton else { return }
            openClassButton.layer?.backgroundColor = (hovering ? buttonHover : buttonBase).cgColor
            openClassButton.layer?.borderColor = (hovering ? self.palette.primaryBlueBorder : self.palette.inputBorder).cgColor
        }
        openClassButton.onHoverChanged?(false)

        let left = NSStackView(views: [title, subtitle])
        left.orientation = .vertical
        left.alignment = .leading
        left.spacing = 4

        let row = NSStackView(views: [left, NSView(), openClassButton])
        row.translatesAutoresizingMaskIntoConstraints = false
        row.orientation = .horizontal
        row.alignment = .centerY

        let card = makeStreamCardShell()
        card.addSubview(row)
        NSLayoutConstraint.activate([
            row.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 14),
            row.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -14),
            row.topAnchor.constraint(equalTo: card.topAnchor, constant: 12),
            row.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -12)
        ])
        return card
    }

    private func makeEmptyState() -> NSView {
        let card = makeStreamCardShell()
        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.orientation = .vertical
        stack.alignment = .centerX
        stack.spacing = 8

        let title = NSTextField(labelWithString: "No stream items yet")
        title.font = NSFont.systemFont(ofSize: 14, weight: .semibold)
        title.textColor = palette.textPrimary

        let subtitle = NSTextField(labelWithString: "Announcements and coursework will appear here.")
        subtitle.font = typography.cardSubtitle
        subtitle.textColor = palette.textSecondary

        stack.addArrangedSubview(title)
        stack.addArrangedSubview(subtitle)
        card.addSubview(stack)
        NSLayoutConstraint.activate([
            stack.centerXAnchor.constraint(equalTo: card.centerXAnchor),
            stack.centerYAnchor.constraint(equalTo: card.centerYAnchor),
            stack.leadingAnchor.constraint(greaterThanOrEqualTo: card.leadingAnchor, constant: 16),
            stack.trailingAnchor.constraint(lessThanOrEqualTo: card.trailingAnchor, constant: -16),
            card.heightAnchor.constraint(equalToConstant: 120)
        ])
        return card
    }

    private func makeMutedLabel(_ text: String) -> NSTextField {
        let label = NSTextField(labelWithString: text)
        label.font = typography.cardSubtitle
        label.textColor = palette.textSecondary
        return label
    }

    private func makeAnnouncementCard(_ item: ClassroomAnnouncement) -> NSView {
        let container = NSStackView()
        container.translatesAutoresizingMaskIntoConstraints = false
        container.orientation = .vertical
        container.alignment = .leading
        container.spacing = 10
        container.addArrangedSubview(makeStreamMetaRow(authorName: defaultAuthorName, date: item.postedAt))
        container.addArrangedSubview(makeBodyLabel(item.text))
        if !item.attachments.isEmpty {
            container.addArrangedSubview(makeAttachmentPreview(item.attachments[0]))
        }
        if let link = item.alternateLink {
            let open = makeStreamFooterActionButton(title: "Open announcement", systemSymbol: "arrow.up.right.square", url: link)
            container.addArrangedSubview(open)
        }
        return wrapInStreamCard(container, url: item.alternateLink)
    }

    private func makeCourseworkCard(_ item: ClassroomCourseWork) -> NSView {
        let container = NSStackView()
        container.translatesAutoresizingMaskIntoConstraints = false
        container.orientation = .vertical
        container.alignment = .leading
        container.spacing = 10

        container.addArrangedSubview(makeStreamMetaRow(authorName: defaultAuthorName, date: item.dueDate))
        let headline = "\(defaultAuthorName) posted a new \(item.subtitle.lowercased()): \(item.title)"
        container.addArrangedSubview(makeBodyLabel(headline))
        if !item.attachments.isEmpty {
            container.addArrangedSubview(makeAttachmentPreview(item.attachments[0]))
        }
        if let link = item.alternateLink {
            let open = makeStreamFooterActionButton(title: "Open item", systemSymbol: "arrow.up.right.square", url: link)
            container.addArrangedSubview(open)
        }
        return wrapInStreamCard(container, url: item.alternateLink)
    }

    private func makeAttachmentsList(_ attachments: [ClassroomAttachment]) -> NSView {
        let stack = NSStackView()
        stack.orientation = .vertical
        stack.alignment = .leading
        stack.spacing = 2

        let header = NSTextField(labelWithString: "Attachments")
        header.font = NSFont.systemFont(ofSize: 12, weight: .semibold)
        header.textColor = palette.textMuted
        stack.addArrangedSubview(header)

        for attachment in attachments {
            let button = NSButton(title: "Open file: \(attachment.title)", target: self, action: #selector(downloadPressed(_:)))
            button.bezelStyle = .inline
            button.font = NSFont.systemFont(ofSize: 12, weight: .medium)
            attachmentByButton[ObjectIdentifier(button)] = attachment
            stack.addArrangedSubview(button)
        }
        return stack
    }

    private func makeStreamMetaRow(authorName: String, date: Date?) -> NSView {
        let avatar = NSImageView()
        avatar.translatesAutoresizingMaskIntoConstraints = false
        if let defaultAuthorAvatar {
            avatar.image = circularNSImage(defaultAuthorAvatar, diameter: 34)
            avatar.contentTintColor = nil
        } else {
            avatar.image = NSImage(systemSymbolName: "person.crop.circle.fill", accessibilityDescription: "Author")
            avatar.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 28, weight: .regular)
            avatar.contentTintColor = palette.textSecondary
        }
        avatar.widthAnchor.constraint(equalToConstant: 34).isActive = true
        avatar.heightAnchor.constraint(equalToConstant: 34).isActive = true

        let name = NSTextField(labelWithString: authorName)
        name.font = NSFont.systemFont(ofSize: 14, weight: .bold)
        name.textColor = palette.textPrimary

        let time = makeMutedLabel(timeText(date))
        time.font = NSFont.systemFont(ofSize: 12, weight: .medium)

        let nameTime = NSStackView(views: [name, time])
        nameTime.orientation = .vertical
        nameTime.alignment = .leading
        nameTime.spacing = 2

        let row = NSStackView(views: [avatar, nameTime, NSView()])
        row.orientation = .horizontal
        row.alignment = .top
        row.distribution = .fill
        return row
    }

    private func makeBodyLabel(_ text: String) -> NSView {
        let body = NSTextField(wrappingLabelWithString: text)
        body.maximumNumberOfLines = 0
        body.font = NSFont.systemFont(ofSize: 15, weight: .regular)
        body.textColor = palette.textPrimary
        return body
    }

    private func makeStreamFooterActionButton(title: String, systemSymbol: String, url: URL) -> NSView {
        let divider = NSBox()
        divider.boxType = .separator
        divider.translatesAutoresizingMaskIntoConstraints = false
        let actionButton = HoverButton(title: title, target: self, action: #selector(openLinkPressed(_:)))
        actionButton.translatesAutoresizingMaskIntoConstraints = false
        actionButton.isBordered = false
        actionButton.bezelStyle = .regularSquare
        actionButton.identifier = NSUserInterfaceItemIdentifier(url.absoluteString)
        actionButton.wantsLayer = true
        actionButton.layer?.cornerRadius = 8
        actionButton.layer?.backgroundColor = NSColor.clear.cgColor
        actionButton.font = NSFont.systemFont(ofSize: 13, weight: .semibold)
        actionButton.contentTintColor = palette.primaryBlue
        actionButton.image = NSImage(systemSymbolName: systemSymbol, accessibilityDescription: title)
        actionButton.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 13, weight: .semibold)
        actionButton.imagePosition = .imageLeading
        actionButton.imageHugsTitle = true
        actionButton.alignment = .left
        actionButton.lineBreakMode = .byTruncatingTail
        actionButton.heightAnchor.constraint(equalToConstant: 28).isActive = true

        let baseHover = NSColor.clear
        let hoverBg = palette.inputBackground.blended(withFraction: 0.20, of: palette.primaryBlue) ?? palette.inputBackground
        actionButton.onHoverChanged = { [weak actionButton] hovering in
            actionButton?.layer?.backgroundColor = (hovering ? hoverBg : baseHover).cgColor
        }
        actionButton.onHoverChanged?(false)

        let container = NSStackView(views: [divider, actionButton])
        container.translatesAutoresizingMaskIntoConstraints = false
        container.orientation = .vertical
        container.alignment = .width
        container.spacing = 8
        return container
    }

    private func makeAttachmentPreview(_ attachment: ClassroomAttachment) -> NSView {
        let preview = HoverTrackingView()
        preview.translatesAutoresizingMaskIntoConstraints = false
        preview.wantsLayer = true
        preview.showsHandCursor = false
        preview.layer?.cornerRadius = 12
        let previewBase = palette.sectionCard
        let previewHover = previewBase.blended(withFraction: 0.14, of: palette.primaryBlue) ?? previewBase
        preview.layer?.backgroundColor = previewBase.cgColor
        preview.layer?.borderWidth = 1
        preview.layer?.borderColor = palette.inputBorder.cgColor
        preview.onHoverChanged = { [weak preview] hovering in
            guard let preview else { return }
            preview.layer?.backgroundColor = (hovering ? previewHover : previewBase).cgColor
            preview.layer?.borderColor = (hovering ? self.palette.primaryBlueBorder : self.palette.inputBorder).cgColor
        }
        preview.onHoverChanged?(false)

        let titleButton = NSButton(title: attachment.title, target: self, action: #selector(downloadPressed(_:)))
        titleButton.translatesAutoresizingMaskIntoConstraints = false
        titleButton.bezelStyle = .inline
        titleButton.font = NSFont.systemFont(ofSize: 16, weight: .semibold)
        titleButton.contentTintColor = palette.primaryBlue
        attachmentByButton[ObjectIdentifier(titleButton)] = attachment

        let type = makeMutedLabel(attachment.mimeType ?? attachment.sourceType.capitalized)
        type.translatesAutoresizingMaskIntoConstraints = false

        let textCol = NSStackView(views: [titleButton, type])
        textCol.translatesAutoresizingMaskIntoConstraints = false
        textCol.orientation = .vertical
        textCol.alignment = .leading
        textCol.spacing = 2

        let thumb = NSImageView()
        thumb.translatesAutoresizingMaskIntoConstraints = false
        thumb.image = NSImage(systemSymbolName: "doc.richtext", accessibilityDescription: nil)
        thumb.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 20, weight: .medium)
        thumb.contentTintColor = palette.textMuted
        thumb.wantsLayer = true
        thumb.layer?.backgroundColor = palette.inputBackground.cgColor
        thumb.layer?.cornerRadius = 8
        thumb.widthAnchor.constraint(equalToConstant: 88).isActive = true

        preview.addSubview(textCol)
        preview.addSubview(thumb)
        NSLayoutConstraint.activate([
            preview.heightAnchor.constraint(equalToConstant: 90),
            textCol.leadingAnchor.constraint(equalTo: preview.leadingAnchor, constant: 12),
            textCol.trailingAnchor.constraint(equalTo: thumb.leadingAnchor, constant: -10),
            textCol.centerYAnchor.constraint(equalTo: preview.centerYAnchor),
            thumb.trailingAnchor.constraint(equalTo: preview.trailingAnchor, constant: -10),
            thumb.topAnchor.constraint(equalTo: preview.topAnchor, constant: 10),
            thumb.bottomAnchor.constraint(equalTo: preview.bottomAnchor, constant: -10)
        ])
        return preview
    }

    private func makeStreamCardShell() -> NSView {
        let card = HoverTrackingView()
        card.translatesAutoresizingMaskIntoConstraints = false
        card.wantsLayer = true
        card.showsHandCursor = false
        card.layer?.cornerRadius = 10
        let baseColor = palette.inputBackground
            .blended(withFraction: 0.32, of: palette.sectionCard)
            ?? palette.inputBackground
        let hoverColor = baseColor.blended(withFraction: 0.12, of: palette.primaryBlue) ?? baseColor
        card.layer?.backgroundColor = baseColor.cgColor
        card.layer?.borderWidth = 1
        card.layer?.borderColor = palette.inputBorder.cgColor
        card.onHoverChanged = { [weak card] hovering in
            guard let card else { return }
            card.layer?.backgroundColor = (hovering ? hoverColor : baseColor).cgColor
            card.layer?.borderColor = (hovering ? self.palette.primaryBlueBorder : self.palette.inputBorder).cgColor
        }
        card.onHoverChanged?(false)
        return card
    }

    private func wrapInStreamCard(_ content: NSView, url: URL? = nil) -> NSView {
        let card = makeStreamCardShell()
        card.addSubview(content)
        NSLayoutConstraint.activate([
            content.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 12),
            content.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -12),
            content.topAnchor.constraint(equalTo: card.topAnchor, constant: 10),
            content.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -10),
            card.widthAnchor.constraint(greaterThanOrEqualToConstant: 220)
        ])
        guard let url else { return card }

        let hit = HoverButton(title: "", target: self, action: #selector(openLinkPressed(_:)))
        hit.translatesAutoresizingMaskIntoConstraints = false
        hit.isBordered = false
        hit.bezelStyle = .regularSquare
        hit.identifier = NSUserInterfaceItemIdentifier(url.absoluteString)
        hit.toolTip = url.absoluteString
        hit.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: hit.leadingAnchor),
            card.trailingAnchor.constraint(equalTo: hit.trailingAnchor),
            card.topAnchor.constraint(equalTo: hit.topAnchor),
            card.bottomAnchor.constraint(equalTo: hit.bottomAnchor)
        ])
        return hit
    }

    private func timeText(_ date: Date?) -> String {
        guard let date else { return "Just now" }
        let formatter = DateFormatter()
        formatter.locale = Locale.current
        formatter.timeStyle = .short
        formatter.dateStyle = .none
        return formatter.string(from: date)
    }
}

private final class HoverFocusScrollView: NSScrollView {
    var onHoverChanged: ((Bool) -> Void)?
    var onMouseDown: (() -> Void)?
    private var hoverTrackingArea: NSTrackingArea?

    override func updateTrackingAreas() {
        super.updateTrackingAreas()
        if let hoverTrackingArea {
            removeTrackingArea(hoverTrackingArea)
        }
        let area = NSTrackingArea(
            rect: bounds,
            options: [.activeInActiveApp, .inVisibleRect, .mouseEnteredAndExited],
            owner: self,
            userInfo: nil
        )
        addTrackingArea(area)
        hoverTrackingArea = area
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        onHoverChanged?(true)
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        onHoverChanged?(false)
    }

    override func acceptsFirstMouse(for event: NSEvent?) -> Bool {
        true
    }

    override func mouseDown(with event: NSEvent) {
        onMouseDown?()
        if let window, !window.isKeyWindow {
            window.makeKeyAndOrderFront(nil)
            return
        }
        // Forward the click straight to the text view so caret placement/blink starts immediately.
        if let textView = documentView as? NSTextView {
            window?.makeFirstResponder(textView)
            textView.mouseDown(with: event)
            return
        }
        super.mouseDown(with: event)
    }
}

private final class ImmediateFocusTextView: NSTextView {
    override var acceptsFirstResponder: Bool { true }

    override func acceptsFirstMouse(for event: NSEvent?) -> Bool {
        true
    }

    @discardableResult
    override func becomeFirstResponder() -> Bool {
        let accepted = super.becomeFirstResponder()
        if accepted {
            ensureCaretVisibleImmediately()
        }
        return accepted
    }

    override func mouseDown(with event: NSEvent) {
        window?.makeFirstResponder(self)
        super.mouseDown(with: event)
        ensureCaretVisibleImmediately()
    }

    func ensureCaretVisibleImmediately() {
        var range = selectedRange()
        if range.location == NSNotFound {
            range = NSRange(location: string.utf16.count, length: 0)
        }
        setSelectedRange(range)
        scrollRangeToVisible(range)
        needsDisplay = true
        displayIfNeeded()
    }
}

// MARK: - Schedule actions (OAuth entry)

private extension ViewController {
    @objc func scheduleReloadButtonPressed(_ sender: NSButton) {
        scheduleReloadClicked()
    }

    @objc func scheduleScrollLeftPressed(_ sender: NSButton) {
        scrollScheduleCards(direction: -1)
    }

    @objc func scheduleScrollRightPressed(_ sender: NSButton) {
        scrollScheduleCards(direction: 1)
    }

    @objc func scheduleCardButtonPressed(_ sender: NSButton) {
        guard storeKitCoordinator.hasPremiumAccess else {
            showPaywall()
            return
        }
        guard let raw = sender.identifier?.rawValue,
              let url = URL(string: raw) else { return }
        openURL(url)
    }

    @objc func scheduleConnectButtonPressed(_ sender: NSButton) {
        scheduleConnectClicked()
    }

    @objc func schedulePageLoadMorePressed(_ sender: NSButton) {
        appendSchedulePageBatchIfNeeded()
    }

    private func scheduleInitialHeadingText() -> String {
        googleOAuth.loadTokens() == nil ? "Connect Google to see your to-do" : scheduleTodayHeadingText()
    }

    private func schedulePageInitialHeadingText() -> String {
        googleOAuth.loadTokens() == nil ? "Connect Google to see your to-do" : scheduleTodayHeadingText()
    }

    private func enrolledPageInitialHeadingText() -> String {
        googleOAuth.loadTokens() == nil ? "Connect Google to see enrolled classes" : "Loading classes…"
    }

    private func teachingPageInitialHeadingText() -> String {
        googleOAuth.loadTokens() == nil ? "Connect Google to see teaching classes" : "Loading classes…"
    }

    @objc func enrolledPageRefreshPressed(_ sender: NSButton) {
        Task { [weak self] in
            await self?.loadEnrolledClasses()
        }
    }

    @objc func teachingPageRefreshPressed(_ sender: NSButton) {
        Task { [weak self] in
            await self?.loadTeachingClasses()
        }
    }

    @objc func scheduleFilterDropdownChanged(_ sender: NSPopUpButton) {
        guard let selectedItem = sender.selectedItem,
              let filter = ScheduleFilter(rawValue: selectedItem.tag) else { return }
        applyScheduleFilter(filter)
    }

    private func applyScheduleFilter(_ filter: ScheduleFilter) {
        scheduleFilter = filter
        scheduleFilterDropdown?.selectItem(at: filter.rawValue)
        Task { [weak self] in
            await self?.loadSchedule()
        }
    }

    @objc func schedulePageFilterDropdownChanged(_ sender: NSPopUpButton) {
        guard let selectedItem = sender.selectedItem,
              let filter = SchedulePageFilter(rawValue: selectedItem.tag) else { return }
        schedulePageFilter = filter
        refreshSchedulePageDateFilterUI()
        applySchedulePageFiltersAndRender()
    }

    @objc func schedulePageDatePickerChanged(_ sender: NSDatePicker) {
        schedulePageFromDate = schedulePageFromDatePicker?.dateValue ?? schedulePageFromDate
        schedulePageToDate = schedulePageToDatePicker?.dateValue ?? schedulePageToDate
    }

    @objc func schedulePageApplyDateRangePressed(_ sender: NSButton) {
        schedulePageFilter = .customRange
        schedulePageFilterDropdown?.selectItem(at: SchedulePageFilter.customRange.rawValue)
        refreshSchedulePageDateFilterUI()
        applySchedulePageFiltersAndRender()
    }

    @objc func schedulePageResetFiltersPressed(_ sender: NSButton) {
        schedulePageFilter = .all
        schedulePageFilterDropdown?.selectItem(at: SchedulePageFilter.all.rawValue)
        let today = Calendar.current.startOfDay(for: Date())
        schedulePageFromDate = today
        schedulePageToDate = today
        schedulePageFromDatePicker?.dateValue = today
        schedulePageToDatePicker?.dateValue = today
        refreshSchedulePageDateFilterUI()
        applySchedulePageFiltersAndRender()
    }

    private func todoDueText(for todo: ClassroomTodoItem) -> String {
        guard let due = todo.dueDate else { return "No due date" }
        let f = DateFormatter()
        f.locale = Locale.current
        f.timeZone = TimeZone.current
        f.dateStyle = .none
        f.timeStyle = .short
        return "Due \(f.string(from: due))"
    }

    private func todoDayText(for todo: ClassroomTodoItem) -> String {
        guard let due = todo.dueDate else { return "Anytime" }
        let f = DateFormatter()
        f.locale = Locale.current
        f.timeZone = TimeZone.current
        f.dateFormat = "EEE, d MMM"
        return f.string(from: due)
    }

    private func scheduleTodayHeadingText() -> String {
        let today = Calendar.current.startOfDay(for: Date())
        let f = DateFormatter()
        f.locale = Locale.current
        f.timeZone = TimeZone.current
        f.dateFormat = "EEEE, d MMM"
        return f.string(from: today)
    }

    private func enrolledPageHeadingText(for courses: [ClassroomCourse]) -> String {
        if googleOAuth.loadTokens() == nil { return "Connect Google to see enrolled classes" }
        if courses.isEmpty { return "No active enrolled classes" }
        return "\(courses.count) enrolled class\(courses.count == 1 ? "" : "es")"
    }

    private func teachingPageHeadingText(for courses: [ClassroomCourse]) -> String {
        if googleOAuth.loadTokens() == nil { return "Connect Google to see teaching classes" }
        if courses.isEmpty { return "No active teaching classes" }
        return "\(courses.count) teaching class\(courses.count == 1 ? "" : "es")"
    }

    private func openURL(_ url: URL) {
        openURLWithRouting(url, policy: inAppBrowserDefaultPolicy)
    }

    private func addPremiumLockOverlayToClassCard(_ card: NSView, message: String) {
        let lockOverlay = NSVisualEffectView()
        lockOverlay.translatesAutoresizingMaskIntoConstraints = false
        lockOverlay.material = darkModeEnabled ? .hudWindow : .popover
        lockOverlay.blendingMode = .withinWindow
        lockOverlay.state = .active
        lockOverlay.wantsLayer = true
        lockOverlay.layer?.cornerRadius = 14
        lockOverlay.layer?.masksToBounds = true
        lockOverlay.layer?.backgroundColor = NSColor.black.withAlphaComponent(darkModeEnabled ? 0.28 : 0.12).cgColor

        let lockLabel = textLabel(message, font: NSFont.systemFont(ofSize: 12, weight: .semibold), color: darkModeEnabled ? .white : .black)
        lockLabel.alignment = .center

        card.addSubview(lockOverlay)
        lockOverlay.addSubview(lockLabel)
        NSLayoutConstraint.activate([
            lockOverlay.leadingAnchor.constraint(equalTo: card.leadingAnchor),
            lockOverlay.trailingAnchor.constraint(equalTo: card.trailingAnchor),
            lockOverlay.topAnchor.constraint(equalTo: card.topAnchor),
            lockOverlay.bottomAnchor.constraint(equalTo: card.bottomAnchor),
            lockLabel.centerXAnchor.constraint(equalTo: lockOverlay.centerXAnchor),
            lockLabel.centerYAnchor.constraint(equalTo: lockOverlay.centerYAnchor),
            lockLabel.leadingAnchor.constraint(greaterThanOrEqualTo: lockOverlay.leadingAnchor, constant: 10),
            lockLabel.trailingAnchor.constraint(lessThanOrEqualTo: lockOverlay.trailingAnchor, constant: -10)
        ])
    }

    private func renderEnrolledClassCards(_ courses: [ClassroomCourse]) {
        guard let stack = enrolledPageCardsStack else { return }
        enrolledCourseByCardID.removeAll()

        stack.arrangedSubviews.forEach { view in
            stack.removeArrangedSubview(view)
            view.removeFromSuperview()
        }

        if courses.isEmpty {
            let empty = roundedContainer(cornerRadius: 12, color: palette.sectionCard)
            empty.translatesAutoresizingMaskIntoConstraints = false
            empty.heightAnchor.constraint(equalToConstant: 128).isActive = true
            styleSurface(empty, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

            let emptyLabel = textLabel(
                googleOAuth.loadTokens() == nil ? "Connect to load classes" : "No enrolled classes found",
                font: typography.cardSubtitle,
                color: palette.textSecondary
            )
            emptyLabel.translatesAutoresizingMaskIntoConstraints = false
            emptyLabel.alignment = .left
            empty.addSubview(emptyLabel)

            NSLayoutConstraint.activate([
                emptyLabel.leadingAnchor.constraint(equalTo: empty.leadingAnchor, constant: 18),
                emptyLabel.trailingAnchor.constraint(equalTo: empty.trailingAnchor, constant: -18),
                emptyLabel.centerYAnchor.constraint(equalTo: empty.centerYAnchor)
            ])
            stack.addArrangedSubview(empty)
            empty.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            return
        }

        for course in courses {
            let card = enrolledClassCardButton(course: course)
            stack.addArrangedSubview(card)
            card.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        }
    }

    private func renderTeachingClassCards(_ courses: [ClassroomCourse]) {
        guard let stack = teachingPageCardsStack else { return }
        teachingCourseByCardID.removeAll()

        stack.arrangedSubviews.forEach { view in
            stack.removeArrangedSubview(view)
            view.removeFromSuperview()
        }

        if courses.isEmpty {
            let empty = roundedContainer(cornerRadius: 12, color: palette.sectionCard)
            empty.translatesAutoresizingMaskIntoConstraints = false
            empty.heightAnchor.constraint(equalToConstant: 128).isActive = true
            styleSurface(empty, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

            let emptyLabel = textLabel(
                googleOAuth.loadTokens() == nil ? "Connect to load classes" : "No teaching classes found",
                font: typography.cardSubtitle,
                color: palette.textSecondary
            )
            emptyLabel.translatesAutoresizingMaskIntoConstraints = false
            emptyLabel.alignment = .left
            empty.addSubview(emptyLabel)

            NSLayoutConstraint.activate([
                emptyLabel.leadingAnchor.constraint(equalTo: empty.leadingAnchor, constant: 18),
                emptyLabel.trailingAnchor.constraint(equalTo: empty.trailingAnchor, constant: -18),
                emptyLabel.centerYAnchor.constraint(equalTo: empty.centerYAnchor)
            ])
            stack.addArrangedSubview(empty)
            empty.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            return
        }

        for course in courses {
            let card = teachingClassCardButton(course: course)
            stack.addArrangedSubview(card)
            card.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        }
    }

    private func enrolledClassCardButton(course: ClassroomCourse) -> NSView {
        let hit = HoverButton(title: "", target: self, action: #selector(enrolledCardButtonPressed(_:)))
        hit.translatesAutoresizingMaskIntoConstraints = false
        hit.isBordered = false
        hit.bezelStyle = .regularSquare
        hit.wantsLayer = true
        hit.identifier = NSUserInterfaceItemIdentifier(course.id)
        enrolledCourseByCardID[course.id] = course
        hit.heightAnchor.constraint(greaterThanOrEqualToConstant: 124).isActive = true

        let card = enrolledClassCard(course: course)
        hit.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: hit.leadingAnchor),
            card.trailingAnchor.constraint(equalTo: hit.trailingAnchor),
            card.topAnchor.constraint(equalTo: hit.topAnchor),
            card.bottomAnchor.constraint(equalTo: hit.bottomAnchor)
        ])
        hit.onHoverChanged = { [weak self, weak card] hovering in
            guard let self, let card else { return }
            let base = self.palette.sectionCard
            let hoverBlend = self.darkModeEnabled ? NSColor.white : NSColor.black
            let hover = base.blended(withFraction: 0.10, of: hoverBlend) ?? base
            if self.storeKitCoordinator.hasPremiumAccess {
                card.layer?.backgroundColor = (hovering ? hover : base).cgColor
            } else {
                card.layer?.backgroundColor = base.cgColor
            }
        }
        hit.onHoverChanged?(false)

        if !storeKitCoordinator.hasPremiumAccess {
            addPremiumLockOverlayToClassCard(card, message: "Get Premium to see classes")
            hit.toolTip = "Premium required. Click to open paywall."
        }

        return hit
    }

    @objc private func enrolledCardButtonPressed(_ sender: NSButton) {
        guard storeKitCoordinator.hasPremiumAccess else {
            showPaywall()
            return
        }
        guard let courseID = sender.identifier?.rawValue,
              let course = enrolledCourseByCardID[courseID] else { return }
        enrolledClassCardClicked(view: sender, course: course)
    }

    @objc private func teachingCardButtonPressed(_ sender: NSButton) {
        guard storeKitCoordinator.hasPremiumAccess else {
            showPaywall()
            return
        }
        guard let courseID = sender.identifier?.rawValue,
              let course = teachingCourseByCardID[courseID] else { return }
        enrolledClassCardClicked(view: sender, course: course)
    }

    private func enrolledClassCard(course: ClassroomCourse) -> NSView {
        let card = roundedContainer(cornerRadius: 14, color: palette.sectionCard)
        card.translatesAutoresizingMaskIntoConstraints = false
        styleSurface(card, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)
        card.heightAnchor.constraint(greaterThanOrEqualToConstant: 124).isActive = true

        let title = textLabel(course.name, font: NSFont.systemFont(ofSize: 17, weight: .semibold), color: palette.textPrimary)
        title.translatesAutoresizingMaskIntoConstraints = false
        title.alignment = .left
        title.maximumNumberOfLines = 2
        title.lineBreakMode = .byWordWrapping

        let sectionText = [course.section, course.room]
            .compactMap { $0?.trimmingCharacters(in: .whitespacesAndNewlines) }
            .filter { !$0.isEmpty }
            .joined(separator: " • ")
        let sectionLabel = textLabel(sectionText.isEmpty ? "Section details unavailable" : sectionText, font: typography.cardSubtitle, color: palette.textSecondary)
        sectionLabel.translatesAutoresizingMaskIntoConstraints = false
        sectionLabel.alignment = .left
        sectionLabel.maximumNumberOfLines = 1
        sectionLabel.lineBreakMode = .byTruncatingTail

        let teachers = course.teacherNames.isEmpty ? "Teacher unavailable" : course.teacherNames.joined(separator: ", ")
        let teacherLabel = textLabel("Teacher: \(teachers)", font: NSFont.systemFont(ofSize: 12, weight: .medium), color: palette.textMuted)
        teacherLabel.translatesAutoresizingMaskIntoConstraints = false
        teacherLabel.alignment = .left
        teacherLabel.maximumNumberOfLines = 2
        teacherLabel.lineBreakMode = .byWordWrapping

        card.addSubview(title)
        card.addSubview(sectionLabel)
        card.addSubview(teacherLabel)
        NSLayoutConstraint.activate([
            title.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 18),
            title.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -18),
            title.topAnchor.constraint(equalTo: card.topAnchor, constant: 16),

            sectionLabel.leadingAnchor.constraint(equalTo: title.leadingAnchor),
            sectionLabel.trailingAnchor.constraint(equalTo: title.trailingAnchor),
            sectionLabel.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 8),

            teacherLabel.leadingAnchor.constraint(equalTo: title.leadingAnchor),
            teacherLabel.trailingAnchor.constraint(equalTo: title.trailingAnchor),
            teacherLabel.topAnchor.constraint(equalTo: sectionLabel.bottomAnchor, constant: 10),
            teacherLabel.bottomAnchor.constraint(lessThanOrEqualTo: card.bottomAnchor, constant: -16)
        ])
        return card
    }

    private func teachingClassCardButton(course: ClassroomCourse) -> NSView {
        let hit = HoverButton(title: "", target: self, action: #selector(teachingCardButtonPressed(_:)))
        hit.translatesAutoresizingMaskIntoConstraints = false
        hit.isBordered = false
        hit.bezelStyle = .regularSquare
        hit.wantsLayer = true
        hit.identifier = NSUserInterfaceItemIdentifier(course.id)
        teachingCourseByCardID[course.id] = course
        hit.heightAnchor.constraint(greaterThanOrEqualToConstant: 124).isActive = true

        let card = enrolledClassCard(course: course)
        hit.addSubview(card)
        NSLayoutConstraint.activate([
            card.leadingAnchor.constraint(equalTo: hit.leadingAnchor),
            card.trailingAnchor.constraint(equalTo: hit.trailingAnchor),
            card.topAnchor.constraint(equalTo: hit.topAnchor),
            card.bottomAnchor.constraint(equalTo: hit.bottomAnchor)
        ])
        hit.onHoverChanged = { [weak self, weak card] hovering in
            guard let self, let card else { return }
            let base = self.palette.sectionCard
            let hoverBlend = self.darkModeEnabled ? NSColor.white : NSColor.black
            let hover = base.blended(withFraction: 0.10, of: hoverBlend) ?? base
            if self.storeKitCoordinator.hasPremiumAccess {
                card.layer?.backgroundColor = (hovering ? hover : base).cgColor
            } else {
                card.layer?.backgroundColor = base.cgColor
            }
        }
        hit.onHoverChanged?(false)

        if !storeKitCoordinator.hasPremiumAccess {
            addPremiumLockOverlayToClassCard(card, message: "Get Premium to see classes")
            hit.toolTip = "Premium required. Click to open paywall."
        }

        return hit
    }

    private func enrolledClassCardClicked(view: NSView, course: ClassroomCourse) {
        Task { [weak self, weak view] in
            guard let self, let view else { return }
            do {
                if self.googleOAuth.loadTokens() == nil {
                    await MainActor.run {
                        self.showSimpleAlert(title: "Connect Google", message: "Connect your Google account to view class details.")
                    }
                    return
                }
                let token = try await self.googleOAuth.validAccessToken(presentingWindow: self.view.window)
                let details = try await self.classroomClient.fetchClassDetails(
                    accessToken: token,
                    courseId: course.id,
                    courseName: course.name
                )
                await MainActor.run {
                    let authorName = course.teacherNames.first ?? "Classroom"
                    self.showEnrolledClassDetailsPopover(details: details, defaultAuthorName: authorName, relativeTo: view)
                }
            } catch {
                await MainActor.run {
                    if self.errorRequiresReconsentForClassroomScopes(error) {
                        _ = try? self.googleOAuth.signOut()
                        self.applyGoogleProfile(nil)
                        self.updateGoogleAuthButtonTitle()
                        self.showSimpleAlert(
                            title: "Reconnect Google",
                            message: "We added new Google Classroom permissions for class announcements. Please reconnect your Google account and grant access."
                        )
                        return
                    }
                    self.showSimpleError("Couldn’t load class details.", error: error)
                }
            }
        }
    }


    private func showEnrolledClassDetailsPopover(details: ClassroomClassDetails, defaultAuthorName: String, relativeTo anchor: NSView) {
        enrolledClassDetailsPopover?.performClose(nil)
        let popover = NSPopover()
        popover.behavior = .transient
        popover.animates = true
        popover.appearance = NSAppearance(named: darkModeEnabled ? .darkAqua : .aqua)
        popover.contentViewController = EnrolledClassDetailsViewController(
            details: details,
            palette: palette,
            typography: typography,
            defaultAuthorName: defaultAuthorName,
            defaultAuthorAvatar: scheduleProfileMenuAvatar,
            onOpenClass: { [weak self] in
                guard let self, let url = details.courseLink else { return }
                self.openURL(url)
            },
            onOpenURL: { [weak self] url in
                self?.openURL(url)
            },
            onDownloadAttachment: { [weak self] attachment in
                self?.downloadClassAttachment(attachment)
            }
        )
        enrolledClassDetailsPopover = popover
        popover.show(relativeTo: anchor.bounds, of: anchor, preferredEdge: .maxX)
    }

    private func downloadClassAttachment(_ attachment: ClassroomAttachment) {
        Task { [weak self] in
            guard let self else { return }
            do {
                let token = try? await self.googleOAuth.validAccessToken(presentingWindow: self.view.window)
                var request = URLRequest(url: attachment.url)
                request.httpMethod = "GET"
                if let token {
                    request.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
                }
                let (data, response) = try await URLSession.shared.data(for: request)
                if let http = response as? HTTPURLResponse, !(200..<300).contains(http.statusCode) {
                    if http.statusCode == 401 || http.statusCode == 403 {
                        await MainActor.run {
                            self.openURL(attachment.url)
                        }
                        return
                    }
                    let body = String(data: data, encoding: .utf8) ?? "<no body>"
                    throw GoogleClassroomClientError.httpStatus(http.statusCode, body)
                }
                if let http = response as? HTTPURLResponse,
                   let contentType = http.value(forHTTPHeaderField: "Content-Type")?.lowercased(),
                   contentType.contains("text/html") {
                    await MainActor.run {
                        self.openURL(attachment.url)
                    }
                    return
                }
                let destination = try self.uniqueDownloadURL(for: attachment)
                try data.write(to: destination)
                await MainActor.run {
                    _ = NSWorkspace.shared.open(destination)
                }
            } catch {
                await MainActor.run {
                    self.showSimpleError("Couldn’t download attachment.", error: error)
                }
            }
        }
    }

    private func uniqueDownloadURL(for attachment: ClassroomAttachment) throws -> URL {
        let fileManager = FileManager.default
        let downloadsDir = try fileManager.url(
            for: .downloadsDirectory,
            in: .userDomainMask,
            appropriateFor: nil,
            create: true
        )

        let preferredName = attachment.title.trimmingCharacters(in: .whitespacesAndNewlines)
        let fallbackName = attachment.url.lastPathComponent.isEmpty ? "attachment" : attachment.url.lastPathComponent
        let originalName = (preferredName.isEmpty ? fallbackName : preferredName)
        let originalExtension = (attachment.url.pathExtension.isEmpty ? URL(fileURLWithPath: originalName).pathExtension : attachment.url.pathExtension)
        let baseName = URL(fileURLWithPath: originalName).deletingPathExtension().lastPathComponent

        var candidate = downloadsDir.appendingPathComponent(originalName)
        if fileManager.fileExists(atPath: candidate.path) == false { return candidate }

        var index = 1
        while true {
            let numbered = "\(baseName)-\(index)\(originalExtension.isEmpty ? "" : ".\(originalExtension)")"
            candidate = downloadsDir.appendingPathComponent(numbered)
            if fileManager.fileExists(atPath: candidate.path) == false {
                return candidate
            }
            index += 1
        }
    }

    private func renderScheduleCards(into stack: NSStackView, todos: [ClassroomTodoItem]) {
        displayedScheduleTodos = todos
        let shouldShowScrollControls = todos.count > 3
        scheduleScrollLeftButton?.isHidden = !shouldShowScrollControls
        scheduleScrollRightButton?.isHidden = !shouldShowScrollControls
        scheduleCardsScrollView?.contentView.setBoundsOrigin(.zero)
        if let scroll = scheduleCardsScrollView {
            scroll.reflectScrolledClipView(scroll.contentView)
        }

        stack.arrangedSubviews.forEach { v in
            stack.removeArrangedSubview(v)
            v.removeFromSuperview()
        }

        if todos.isEmpty {
            let empty = roundedContainer(cornerRadius: 10, color: palette.sectionCard)
            empty.translatesAutoresizingMaskIntoConstraints = false
            empty.widthAnchor.constraint(equalToConstant: 240).isActive = true
            empty.heightAnchor.constraint(equalToConstant: 150).isActive = true
            styleSurface(empty, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)

            let label = textLabel(googleOAuth.loadTokens() == nil ? "Connect to load to-do" : "No work due", font: typography.cardSubtitle, color: palette.textSecondary)
            label.translatesAutoresizingMaskIntoConstraints = false
            empty.addSubview(label)
            NSLayoutConstraint.activate([
                label.centerXAnchor.constraint(equalTo: empty.centerXAnchor),
                label.centerYAnchor.constraint(equalTo: empty.centerYAnchor)
            ])
            stack.addArrangedSubview(empty)
            return
        }

        for todo in todos {
            stack.addArrangedSubview(scheduleCard(todo: todo))
        }
    }

    private func filteredTodos(_ todos: [ClassroomTodoItem]) -> [ClassroomTodoItem] {
        switch scheduleFilter {
        case .all:
            return todos
        case .today:
            let start = Calendar.current.startOfDay(for: Date())
            let end = Calendar.current.date(byAdding: .day, value: 1, to: start) ?? start.addingTimeInterval(86400)
            return todos.filter { ($0.dueDate ?? .distantPast) >= start && ($0.dueDate ?? .distantPast) < end }
        case .week:
            let now = Date()
            let end = Calendar.current.date(byAdding: .day, value: 7, to: now) ?? now.addingTimeInterval(7 * 86400)
            return todos.filter {
                guard let due = $0.dueDate else { return false }
                return due >= now && due <= end
            }
        }
    }

    private func filteredTodosForSchedulePage(_ todos: [ClassroomTodoItem]) -> [ClassroomTodoItem] {
        let calendar = Calendar.current
        switch schedulePageFilter {
        case .all:
            return todos
        case .today:
            let start = calendar.startOfDay(for: Date())
            let end = calendar.date(byAdding: .day, value: 1, to: start) ?? start.addingTimeInterval(86400)
            return todos.filter {
                guard let due = $0.dueDate else { return false }
                return due >= start && due < end
            }
        case .week:
            let now = Date()
            let end = calendar.date(byAdding: .day, value: 7, to: now) ?? now.addingTimeInterval(7 * 86400)
            return todos.filter {
                guard let due = $0.dueDate else { return false }
                return due >= now && due <= end
            }
        case .month:
            let now = Date()
            let end = calendar.date(byAdding: .month, value: 1, to: now) ?? now.addingTimeInterval(30 * 86400)
            return todos.filter {
                guard let due = $0.dueDate else { return false }
                return due >= now && due <= end
            }
        case .customRange:
            let start = calendar.startOfDay(for: schedulePageFromDate)
            let inclusiveEndDay = calendar.startOfDay(for: schedulePageToDate)
            guard let end = calendar.date(byAdding: .day, value: 1, to: inclusiveEndDay) else {
                return todos
            }
            return todos.filter {
                guard let due = $0.dueDate else { return false }
                return due >= start && due < end
            }
        }
    }

    private func refreshSchedulePageDateFilterUI() {
        let isCustom = schedulePageFilter == .customRange
        schedulePageFromDatePicker?.isEnabled = isCustom
        schedulePageToDatePicker?.isEnabled = isCustom
        let dim: CGFloat = isCustom ? 1.0 : 0.65
        schedulePageFromDatePicker?.alphaValue = 1
        schedulePageToDatePicker?.alphaValue = 1
        schedulePageFromDatePicker?.superview?.alphaValue = dim
        schedulePageToDatePicker?.superview?.alphaValue = dim
    }

    private func schedulePageHasValidCustomRange() -> Bool {
        let start = Calendar.current.startOfDay(for: schedulePageFromDate)
        let end = Calendar.current.startOfDay(for: schedulePageToDate)
        return start <= end
    }

    private func setSchedulePageRangeError(_ message: String?) {
        guard let label = schedulePageRangeErrorLabel else { return }
        label.stringValue = message ?? ""
        label.isHidden = message == nil
    }

    private func applySchedulePageFiltersAndRender() {
        schedulePageFromDate = schedulePageFromDatePicker?.dateValue ?? schedulePageFromDate
        schedulePageToDate = schedulePageToDatePicker?.dateValue ?? schedulePageToDate
        if schedulePageFilter == .customRange && !schedulePageHasValidCustomRange() {
            setSchedulePageRangeError("Start date must be on or before end date.")
            schedulePageFilteredTodos = []
            schedulePageVisibleCount = 0
            renderSchedulePageCards()
            schedulePageDateHeadingLabel?.stringValue = "Invalid custom date range"
            return
        }

        setSchedulePageRangeError(nil)
        schedulePageFilteredTodos = filteredTodosForSchedulePage(scheduleCachedTodos)
        schedulePageVisibleCount = min(schedulePageBatchSize, schedulePageFilteredTodos.count)
        renderSchedulePageCards()
        schedulePageDateHeadingLabel?.stringValue = scheduleTodayHeadingText()
    }

    private func appendSchedulePageBatchIfNeeded() {
        guard schedulePageVisibleCount < schedulePageFilteredTodos.count else { return }
        let nextCount = min(schedulePageVisibleCount + schedulePageBatchSize, schedulePageFilteredTodos.count)
        guard nextCount > schedulePageVisibleCount else { return }
        schedulePageVisibleCount = nextCount
        renderSchedulePageCards()
        // If we're still near the bottom after adding a batch (large viewport),
        // immediately evaluate again so pagination keeps advancing in chunks of 6.
        DispatchQueue.main.async { [weak self] in
            self?.schedulePageScrolled()
        }
    }

    private func schedulePageScrolled() {
        guard let scroll = schedulePageCardsScrollView else { return }
        let contentBounds = scroll.contentView.bounds
        let contentHeight = scroll.documentView?.bounds.height ?? 0
        guard contentHeight > 0 else { return }
        let remaining = contentHeight - (contentBounds.origin.y + contentBounds.height)
        if remaining <= 200 {
            appendSchedulePageBatchIfNeeded()
        }
    }

    private func renderSchedulePageCards() {
        guard let stack = schedulePageCardsStack else { return }
        stack.arrangedSubviews.forEach { v in
            stack.removeArrangedSubview(v)
            v.removeFromSuperview()
        }

        let visibleTodos = Array(schedulePageFilteredTodos.prefix(schedulePageVisibleCount))
        if visibleTodos.isEmpty {
            let empty = roundedContainer(cornerRadius: 10, color: palette.sectionCard)
            empty.translatesAutoresizingMaskIntoConstraints = false
            empty.heightAnchor.constraint(equalToConstant: 140).isActive = true
            styleSurface(empty, borderColor: palette.inputBorder, borderWidth: 1, shadow: false)
            let label = textLabel(googleOAuth.loadTokens() == nil ? "Connect to load to-do" : "No work for selected filters", font: typography.cardSubtitle, color: palette.textSecondary)
            label.translatesAutoresizingMaskIntoConstraints = false
            empty.addSubview(label)
            NSLayoutConstraint.activate([
                label.centerXAnchor.constraint(equalTo: empty.centerXAnchor),
                label.centerYAnchor.constraint(equalTo: empty.centerYAnchor)
            ])
            stack.addArrangedSubview(empty)
            empty.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            return
        }

        var index = 0
        while index < visibleTodos.count {
            let row = NSStackView()
            row.translatesAutoresizingMaskIntoConstraints = false
            row.userInterfaceLayoutDirection = .leftToRight
            row.orientation = .horizontal
            row.alignment = .top
            row.spacing = schedulePageCardSpacing
            row.distribution = .fillEqually
            let rowEnd = min(index + schedulePageCardsPerRow, visibleTodos.count)
            for todo in visibleTodos[index..<rowEnd] {
                row.addArrangedSubview(scheduleCard(todo: todo, useFlexibleWidth: true, contentHeight: schedulePageCardHeight))
            }
            stack.addArrangedSubview(row)
            row.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
            index = rowEnd
        }

        if schedulePageVisibleCount < schedulePageFilteredTodos.count {
            let pagination = NSStackView()
            pagination.translatesAutoresizingMaskIntoConstraints = false
            pagination.orientation = .horizontal
            pagination.alignment = .centerY
            pagination.spacing = 10

            let moreLabel = textLabel(
                "Showing \(schedulePageVisibleCount) of \(schedulePageFilteredTodos.count)",
                font: NSFont.systemFont(ofSize: 12, weight: .medium),
                color: palette.textMuted
            )
            pagination.addArrangedSubview(moreLabel)

            let spacer = NSView()
            spacer.translatesAutoresizingMaskIntoConstraints = false
            spacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
            pagination.addArrangedSubview(spacer)

            stack.addArrangedSubview(pagination)
            pagination.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        }
    }

    private func scrollScheduleCards(direction: Int) {
        guard let scroll = scheduleCardsScrollView else { return }
        let contentBounds = scroll.contentView.bounds
        let step = max(220, contentBounds.width * 0.7)
        let proposedX = contentBounds.origin.x + (CGFloat(direction) * step)
        let maxX = max(0, scroll.documentView?.bounds.width ?? 0 - contentBounds.width)
        let nextX = min(max(0, proposedX), maxX)
        scroll.contentView.animator().setBoundsOrigin(NSPoint(x: nextX, y: 0))
        scroll.reflectScrolledClipView(scroll.contentView)
    }

    private func errorRequiresReconsentForClassroomScopes(_ error: Error) -> Bool {
        if case let GoogleClassroomClientError.httpStatus(status, body) = error {
            guard status == 403 else { return false }
            return body.contains("ACCESS_TOKEN_SCOPE_INSUFFICIENT") || body.contains("insufficient authentication scopes")
        }
        return false
    }

    private func loadSchedule() async {
        do {
            if googleOAuth.loadTokens() == nil {
                await MainActor.run {
                    updateGoogleAuthButtonTitle()
                    applyGoogleProfile(nil)
                    scheduleDateHeadingLabel?.stringValue = "Connect Google to see your to-do"
                    schedulePageDateHeadingLabel?.stringValue = "Connect Google to see your to-do"
                    if let stack = scheduleCardsStack {
                        renderScheduleCards(into: stack, todos: [])
                    }
                    scheduleCachedTodos = []
                    applySchedulePageFiltersAndRender()
                }
                return
            }

            let token = try await googleOAuth.validAccessToken(presentingWindow: view.window)
            let profile = try? await googleOAuth.fetchUserProfile(accessToken: token)
            let todos = try await classroomClient.fetchTodo(accessToken: token)
            let filtered = filteredTodos(todos)

            await MainActor.run {
                updateGoogleAuthButtonTitle()
                applyGoogleProfile(profile.map { self.makeGoogleProfileDisplay(from: $0) })
                scheduleDateHeadingLabel?.stringValue = scheduleTodayHeadingText()
                if let stack = scheduleCardsStack {
                    renderScheduleCards(into: stack, todos: filtered)
                }
                scheduleCachedTodos = todos
                applySchedulePageFiltersAndRender()
            }
        } catch {
            await MainActor.run {
                if errorRequiresReconsentForClassroomScopes(error) {
                    _ = try? googleOAuth.signOut()
                    applyGoogleProfile(nil)
                    updateGoogleAuthButtonTitle()
                    scheduleDateHeadingLabel?.stringValue = "Reconnect Google to enable Classroom permissions"
                    schedulePageDateHeadingLabel?.stringValue = "Reconnect Google to enable Classroom permissions"
                    if let stack = scheduleCardsStack {
                        renderScheduleCards(into: stack, todos: [])
                    }
                    scheduleCachedTodos = []
                    applySchedulePageFiltersAndRender()
                    showSimpleAlert(
                        title: "Reconnect Google",
                        message: "We added Google Classroom permissions. Please connect your Google account again so Google can grant access to assignments and quizzes."
                    )
                    return
                }
                updateGoogleAuthButtonTitle()
                if googleOAuth.loadTokens() == nil {
                    applyGoogleProfile(nil)
                }
                scheduleDateHeadingLabel?.stringValue = "Couldn’t load to-do"
                schedulePageDateHeadingLabel?.stringValue = "Couldn’t load to-do"
                if let stack = scheduleCardsStack {
                    renderScheduleCards(into: stack, todos: [])
                }
                scheduleCachedTodos = []
                applySchedulePageFiltersAndRender()
                showSimpleError("Couldn’t load to-do.", error: error)
            }
        }
    }

    private func loadEnrolledClasses() async {
        do {
            if googleOAuth.loadTokens() == nil {
                await MainActor.run {
                    enrolledCachedCourses = []
                    enrolledPageHeadingLabel?.stringValue = "Connect Google to see enrolled classes"
                    renderEnrolledClassCards([])
                }
                return
            }

            let token = try await googleOAuth.validAccessToken(presentingWindow: view.window)
            let courses = try await classroomClient.fetchEnrolledCourses(accessToken: token)

            await MainActor.run {
                enrolledCachedCourses = courses
                enrolledPageHeadingLabel?.stringValue = enrolledPageHeadingText(for: courses)
                renderEnrolledClassCards(courses)
            }
        } catch {
            await MainActor.run {
                if errorRequiresReconsentForClassroomScopes(error) {
                    _ = try? googleOAuth.signOut()
                    applyGoogleProfile(nil)
                    updateGoogleAuthButtonTitle()
                    enrolledCachedCourses = []
                    enrolledPageHeadingLabel?.stringValue = "Reconnect Google to enable Classroom permissions"
                    renderEnrolledClassCards([])
                    showSimpleAlert(
                        title: "Reconnect Google",
                        message: "We added Google Classroom permissions. Please connect your Google account again so Google can grant access to your classes."
                    )
                    return
                }
                enrolledCachedCourses = []
                enrolledPageHeadingLabel?.stringValue = "Couldn’t load enrolled classes"
                renderEnrolledClassCards([])
                showSimpleError("Couldn’t load enrolled classes.", error: error)
            }
        }
    }

    private func loadTeachingClasses() async {
        do {
            if googleOAuth.loadTokens() == nil {
                await MainActor.run {
                    teachingCachedCourses = []
                    teachingPageHeadingLabel?.stringValue = "Connect Google to see teaching classes"
                    renderTeachingClassCards([])
                }
                return
            }

            let token = try await googleOAuth.validAccessToken(presentingWindow: view.window)
            let courses = try await classroomClient.fetchTeachingCourses(accessToken: token)

            await MainActor.run {
                teachingCachedCourses = courses
                teachingPageHeadingLabel?.stringValue = teachingPageHeadingText(for: courses)
                renderTeachingClassCards(courses)
            }
        } catch {
            await MainActor.run {
                if errorRequiresReconsentForClassroomScopes(error) {
                    _ = try? googleOAuth.signOut()
                    applyGoogleProfile(nil)
                    updateGoogleAuthButtonTitle()
                    teachingCachedCourses = []
                    teachingPageHeadingLabel?.stringValue = "Reconnect Google to enable Classroom permissions"
                    renderTeachingClassCards([])
                    showSimpleAlert(
                        title: "Reconnect Google",
                        message: "We added Google Classroom permissions. Please connect your Google account again so Google can grant access to your classes."
                    )
                    return
                }
                teachingCachedCourses = []
                teachingPageHeadingLabel?.stringValue = "Couldn’t load teaching classes"
                renderTeachingClassCards([])
                showSimpleError("Couldn’t load teaching classes.", error: error)
            }
        }
    }

    func showScheduleHelp() {
        let alert = NSAlert()
        alert.messageText = "Google Classroom to-do"
        alert.informativeText = "To show assignments and quizzes, connect your Google account. You’ll need a Google OAuth client ID (Desktop) and a redirect URI matching the app’s callback scheme."
        alert.addButton(withTitle: "OK")
        alert.runModal()
    }

    func scheduleReloadClicked() {
        Task { [weak self] in
            guard let self else { return }
            do {
                try await self.ensureGoogleClientIdConfigured(presentingWindow: self.view.window)
                _ = try await self.googleOAuth.validAccessToken(presentingWindow: self.view.window)
                await MainActor.run {
                    self.scheduleDateHeadingLabel?.stringValue = "Refreshing…"
                    self.pageCache[.joinMeetings] = nil
                    self.pageCache[.photo] = nil
                    self.pageCache[.enrolled] = nil
                    self.pageCache[.teaching] = nil
                    self.showSidebarPage(self.selectedSidebarPage)
                }
                await self.loadSchedule()
            } catch {
                await MainActor.run {
                    self.showSimpleError("Couldn’t refresh schedule.", error: error)
                }
            }
        }
    }

    func scheduleConnectClicked() {
        Task { [weak self] in
            guard let self else { return }
            do {
                if self.googleOAuth.loadTokens() != nil {
                    await MainActor.run { self.showGoogleAccountMenu() }
                    return
                }

                try await self.ensureGoogleClientIdConfigured(presentingWindow: self.view.window)
                let token = try await self.googleOAuth.validAccessToken(presentingWindow: self.view.window)
                let profile = try? await self.googleOAuth.fetchUserProfile(accessToken: token)
                await MainActor.run {
                    self.updateGoogleAuthButtonTitle()
                    self.applyGoogleProfile(profile.map { self.makeGoogleProfileDisplay(from: $0) })
                    self.pageCache[.joinMeetings] = nil
                    self.pageCache[.photo] = nil
                    self.pageCache[.enrolled] = nil
                    self.pageCache[.teaching] = nil
                    self.pageCache[.settings] = nil
                    self.showSidebarPage(self.selectedSidebarPage)
                }
            } catch {
                self.showSimpleError("Couldn’t connect Google account.", error: error)
            }
        }
    }

    private func showGoogleAccountMenu() {
        guard let button = scheduleGoogleAuthButton else { return }
        if googleAccountPopover?.isShown == true {
            googleAccountPopover?.performClose(nil)
            googleAccountPopover = nil
            return
        }

        let popover = NSPopover()
        popover.behavior = .transient
        popover.animates = true
        popover.appearance = NSAppearance(named: darkModeEnabled ? .darkAqua : .aqua)

        let name = scheduleCurrentProfile?.name ?? "Google account"
        let email = scheduleCurrentProfile?.email ?? "Signed in"
        let avatar = scheduleProfileMenuAvatar

        popover.contentViewController = GoogleAccountMenuViewController(
            palette: palette,
            darkModeEnabled: darkModeEnabled,
            displayName: name,
            email: email,
            avatar: avatar,
            onSignOut: { [weak self] in
                self?.googleAccountPopover?.performClose(nil)
                self?.googleAccountPopover = nil
                self?.performGoogleSignOut()
            }
        )

        googleAccountPopover = popover
        popover.show(relativeTo: button.bounds, of: button, preferredEdge: .minY)
    }

    private func performGoogleSignOut() {
        do {
            try googleOAuth.signOut()
            applyGoogleProfile(nil)
            updateGoogleAuthButtonTitle()
            pageCache[.joinMeetings] = nil
            pageCache[.photo] = nil
            pageCache[.enrolled] = nil
            pageCache[.teaching] = nil
            pageCache[.settings] = nil
            showSidebarPage(selectedSidebarPage)
            Task { [weak self] in
                await self?.loadSchedule()
            }
        } catch {
            showSimpleError("Couldn’t logout Google account.", error: error)
        }
    }

    private func updateGoogleAuthButtonTitle() {
        let signedIn = (googleOAuth.loadTokens() != nil)
        guard let button = scheduleGoogleAuthButton else { return }

        let profileName = scheduleCurrentProfile?.name ?? "Google account"
        let ringHostInset: CGFloat = signedIn ? 14 : 0
        scheduleGoogleAuthHostPadWidthConstraint?.constant = ringHostInset
        scheduleGoogleAuthHostPadHeightConstraint?.constant = ringHostInset
        scheduleGoogleAuthHostView?.setAvatarRingMode(signedIn)
        scheduleGoogleAuthHostView?.updateRingAppearance(isDark: darkModeEnabled, accent: palette.primaryBlue)
        if signedIn == false {
            scheduleGoogleAuthHostView?.setProfileHoverActive(false)
        }

        if signedIn {
            button.setAccessibilityLabel("\(profileName), Google account")
            button.attributedTitle = NSAttributedString(string: "")
            button.imagePosition = .imageOnly
            button.imageScaling = .scaleProportionallyDown
            button.symbolConfiguration = nil
            scheduleGoogleAuthButtonHeightConstraint?.constant = scheduleGoogleSignedInAvatarSize
            scheduleGoogleAuthButtonWidthConstraint?.constant = scheduleGoogleSignedInAvatarSize
            button.layer?.cornerRadius = scheduleGoogleSignedInAvatarSize / 2

            let symbol = NSImage(systemSymbolName: "person.crop.circle.fill", accessibilityDescription: "Profile")
            if let symbol {
                let sized = resizedImage(symbol, to: NSSize(width: scheduleGoogleSignedInAvatarSize, height: scheduleGoogleSignedInAvatarSize))
                button.image = sized
                button.contentTintColor = palette.textSecondary
            } else {
                button.image = nil
                button.contentTintColor = nil
            }
            scheduleProfileMenuAvatar = button.image
        } else {
            button.setAccessibilityLabel("Sign in with Google")
            let title = "Sign in with Google"
            let titleFont = NSFont.systemFont(ofSize: 14, weight: .medium)
            let titleColor = darkModeEnabled ? NSColor(calibratedWhite: 0.96, alpha: 1) : NSColor(calibratedRed: 0.13, green: 0.14, blue: 0.16, alpha: 1)
            button.attributedTitle = NSAttributedString(string: title, attributes: [
                .font: titleFont,
                .foregroundColor: titleColor
            ])
            let textWidth = (title as NSString).size(withAttributes: [.font: titleFont]).width
            let idealWidth = ceil(textWidth + 80)
            scheduleGoogleAuthButtonWidthConstraint?.constant = min(320, max(188, idealWidth))
            scheduleGoogleAuthButtonHeightConstraint?.constant = 42
            button.layer?.cornerRadius = 21

            button.imagePosition = .imageLeading
            button.imageScaling = .scaleNone
            if let g = NSImage(named: "GoogleGLogo") {
                button.image = paddedTrailingImage(g, iconSize: NSSize(width: 22, height: 22), trailingPadding: 8)
            } else {
                button.image = nil
            }
            button.contentTintColor = nil
        }

        applyGoogleAuthButtonSurface()
    }

    private func makeGoogleProfileDisplay(from profile: GoogleUserProfile) -> GoogleProfileDisplay {
        let cleanedName = profile.name?.trimmingCharacters(in: .whitespacesAndNewlines)
        let cleanedEmail = profile.email?.trimmingCharacters(in: .whitespacesAndNewlines)
        return GoogleProfileDisplay(
            name: (cleanedName?.isEmpty == false ? cleanedName : nil) ?? "Google User",
            email: (cleanedEmail?.isEmpty == false ? cleanedEmail : nil) ?? "Signed in",
            pictureURL: profile.picture.flatMap(URL.init(string:))
        )
    }

    private func applyGoogleProfile(_ profile: GoogleProfileDisplay?) {
        scheduleProfileImageTask?.cancel()
        scheduleProfileImageTask = nil
        if profile == nil {
            scheduleProfileMenuAvatar = nil
        }
        scheduleCurrentProfile = profile

        updateGoogleAuthButtonTitle()

        guard let profile, let pictureURL = profile.pictureURL else { return }
        let avatarDiameter = scheduleGoogleSignedInAvatarSize
        scheduleProfileImageTask = Task { [weak self] in
            do {
                let (data, _) = try await URLSession.shared.data(from: pictureURL)
                if Task.isCancelled { return }
                guard let image = NSImage(data: data) else { return }
                await MainActor.run { [weak self] in
                    guard let self else { return }
                    let rounded = self.circularProfileImage(image, diameter: avatarDiameter)
                    self.scheduleProfileMenuAvatar = circularNSImage(rounded, diameter: 48)
                    self.scheduleGoogleAuthButton?.image = rounded
                    self.scheduleGoogleAuthButton?.contentTintColor = nil
                }
            } catch {
                // Keep placeholder avatar if image fetch fails.
            }
        }
    }

    private func resizedImage(_ image: NSImage, to size: NSSize) -> NSImage {
        let result = NSImage(size: size)
        result.lockFocus()
        image.draw(in: NSRect(origin: .zero, size: size),
                   from: NSRect(origin: .zero, size: image.size),
                   operation: .copy,
                   fraction: 1.0)
        result.unlockFocus()
        result.isTemplate = false
        return result
    }

    /// Clips a photo to a circle for the signed-in avatar (Google userinfo `picture` URLs are usually square).
    private func circularProfileImage(_ image: NSImage, diameter: CGFloat) -> NSImage {
        circularNSImage(image, diameter: diameter)
    }

    private func paddedTrailingImage(_ image: NSImage, iconSize: NSSize, trailingPadding: CGFloat) -> NSImage {
        let base = resizedImage(image, to: iconSize)
        let canvas = NSSize(width: iconSize.width + trailingPadding, height: iconSize.height)
        let result = NSImage(size: canvas)
        result.lockFocus()
        base.draw(in: NSRect(x: 0, y: 0, width: iconSize.width, height: iconSize.height),
                  from: NSRect(origin: .zero, size: base.size),
                  operation: .copy,
                  fraction: 1.0)
        result.unlockFocus()
        result.isTemplate = false
        return result
    }

    private func applyGoogleAuthButtonSurface() {
        guard let button = scheduleGoogleAuthButton else { return }
        let signedIn = (googleOAuth.loadTokens() != nil)
        let isDark = darkModeEnabled
        if signedIn {
            button.layer?.backgroundColor = NSColor.clear.cgColor
            button.layer?.borderWidth = 0
            scheduleGoogleAuthHostView?.updateRingAppearance(isDark: isDark, accent: palette.primaryBlue)
            return
        }
        let baseBackground = isDark
            ? NSColor(calibratedRed: 8.0 / 255.0, green: 14.0 / 255.0, blue: 24.0 / 255.0, alpha: 1)
            : NSColor.white
        let hoverBlend = isDark ? NSColor.white : NSColor.black
        let hoverBackground = baseBackground.blended(withFraction: 0.07, of: hoverBlend) ?? baseBackground
        let baseBorder = isDark
            ? NSColor(calibratedWhite: 0.50, alpha: 1)
            : NSColor(calibratedWhite: 0.72, alpha: 1)
        let hoverBorder = isDark
            ? NSColor(calibratedWhite: 0.62, alpha: 1)
            : NSColor(calibratedWhite: 0.56, alpha: 1)
        button.layer?.borderWidth = 1
        button.layer?.backgroundColor = (scheduleGoogleAuthHovering ? hoverBackground : baseBackground).cgColor
        button.layer?.borderColor = (scheduleGoogleAuthHovering ? hoverBorder : baseBorder).cgColor
    }

    @MainActor
    func ensureGoogleClientIdConfigured(presentingWindow: NSWindow?) async throws {
        if googleOAuth.configuredClientId() != nil, googleOAuth.configuredClientSecret() != nil { return }

        let alert = NSAlert()
        alert.messageText = "Enter Google OAuth credentials"
        alert.informativeText = "Paste the OAuth Client ID and Client Secret from your downloaded Desktop OAuth JSON."

        let accessory = NSStackView()
        accessory.orientation = .vertical
        accessory.spacing = 8
        accessory.alignment = .leading

        let idField = NSTextField(string: googleOAuth.configuredClientId() ?? "")
        idField.placeholderString = "Client ID (....apps.googleusercontent.com)"
        idField.frame = NSRect(x: 0, y: 0, width: 460, height: 24)

        let secretField = NSSecureTextField(string: googleOAuth.configuredClientSecret() ?? "")
        secretField.placeholderString = "Client Secret (GOCSPX-...)"
        secretField.frame = NSRect(x: 0, y: 0, width: 460, height: 24)

        accessory.addArrangedSubview(idField)
        accessory.addArrangedSubview(secretField)
        alert.accessoryView = accessory

        alert.addButton(withTitle: "Save")
        alert.addButton(withTitle: "Cancel")

        // Keep this synchronous to avoid additional sheet state handling.
        let response = alert.runModal()
        if response != .alertFirstButtonReturn { throw GoogleOAuthError.missingClientId }

        let idValue = idField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
        let secretValue = secretField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
        if idValue.isEmpty { throw GoogleOAuthError.missingClientId }
        if secretValue.isEmpty { throw GoogleOAuthError.missingClientSecret }

        googleOAuth.setClientIdForTesting(idValue)
        googleOAuth.setClientSecretForTesting(secretValue)
    }

    func showSimpleError(_ title: String, error: Error) {
        DispatchQueue.main.async {
            let alert = NSAlert()
            alert.alertStyle = .warning
            alert.messageText = title
            alert.informativeText = error.localizedDescription
            alert.addButton(withTitle: "OK")
            alert.runModal()
        }
    }
}

private struct Palette {
    let pageBackground: NSColor
    let sidebarBackground: NSColor
    let sectionCard: NSColor
    let tabBarBackground: NSColor
    let tabIdleBackground: NSColor
    let inputBackground: NSColor
    let inputBorder: NSColor
    let primaryBlue: NSColor
    let primaryBlueBorder: NSColor
    let cancelButton: NSColor
    let meetingBadge: NSColor
    let separator: NSColor
    let textPrimary: NSColor
    let textSecondary: NSColor
    let textTertiary: NSColor
    let textMuted: NSColor

    init(isDarkMode: Bool) {
        if isDarkMode {
            pageBackground = NSColor(calibratedRed: 10.0 / 255.0, green: 11.0 / 255.0, blue: 12.0 / 255.0, alpha: 1)
            sidebarBackground = NSColor(calibratedRed: 16.0 / 255.0, green: 17.0 / 255.0, blue: 19.0 / 255.0, alpha: 1)
            sectionCard = NSColor(calibratedRed: 22.0 / 255.0, green: 23.0 / 255.0, blue: 26.0 / 255.0, alpha: 1)
            tabBarBackground = NSColor(calibratedRed: 22.0 / 255.0, green: 23.0 / 255.0, blue: 26.0 / 255.0, alpha: 1)
            tabIdleBackground = NSColor(calibratedRed: 22.0 / 255.0, green: 23.0 / 255.0, blue: 26.0 / 255.0, alpha: 1)
            inputBackground = NSColor(calibratedRed: 20.0 / 255.0, green: 21.0 / 255.0, blue: 24.0 / 255.0, alpha: 1)
            inputBorder = NSColor(calibratedRed: 38.0 / 255.0, green: 40.0 / 255.0, blue: 44.0 / 255.0, alpha: 1)
            primaryBlue = NSColor(calibratedRed: 15.0 / 255.0, green: 157.0 / 255.0, blue: 88.0 / 255.0, alpha: 1)
            primaryBlueBorder = NSColor(calibratedRed: 13.0 / 255.0, green: 134.0 / 255.0, blue: 73.0 / 255.0, alpha: 1)
            cancelButton = NSColor(calibratedRed: 20.0 / 255.0, green: 21.0 / 255.0, blue: 24.0 / 255.0, alpha: 1)
            meetingBadge = NSColor(calibratedRed: 0.88, green: 0.66, blue: 0.14, alpha: 1)
            separator = NSColor(calibratedRed: 26.0 / 255.0, green: 27.0 / 255.0, blue: 30.0 / 255.0, alpha: 1)
            textPrimary = NSColor(calibratedWhite: 0.98, alpha: 1)
            textSecondary = NSColor(calibratedWhite: 0.78, alpha: 1)
            textTertiary = NSColor(calibratedWhite: 0.66, alpha: 1)
            textMuted = NSColor(calibratedWhite: 0.44, alpha: 1)
        } else {
            pageBackground = NSColor(calibratedRed: 244.0 / 255.0, green: 246.0 / 255.0, blue: 249.0 / 255.0, alpha: 1)
            sidebarBackground = NSColor(calibratedRed: 232.0 / 255.0, green: 236.0 / 255.0, blue: 242.0 / 255.0, alpha: 1)
            sectionCard = NSColor.white
            tabBarBackground = NSColor.white
            tabIdleBackground = NSColor.white
            inputBackground = NSColor(calibratedRed: 247.0 / 255.0, green: 249.0 / 255.0, blue: 252.0 / 255.0, alpha: 1)
            inputBorder = NSColor(calibratedRed: 211.0 / 255.0, green: 218.0 / 255.0, blue: 228.0 / 255.0, alpha: 1)
            primaryBlue = NSColor(calibratedRed: 15.0 / 255.0, green: 157.0 / 255.0, blue: 88.0 / 255.0, alpha: 1)
            primaryBlueBorder = NSColor(calibratedRed: 13.0 / 255.0, green: 134.0 / 255.0, blue: 73.0 / 255.0, alpha: 1)
            cancelButton = NSColor(calibratedRed: 240.0 / 255.0, green: 243.0 / 255.0, blue: 248.0 / 255.0, alpha: 1)
            meetingBadge = NSColor(calibratedRed: 0.88, green: 0.66, blue: 0.14, alpha: 1)
            separator = NSColor(calibratedRed: 212.0 / 255.0, green: 219.0 / 255.0, blue: 229.0 / 255.0, alpha: 1)
            textPrimary = NSColor(calibratedRed: 32.0 / 255.0, green: 38.0 / 255.0, blue: 47.0 / 255.0, alpha: 1)
            textSecondary = NSColor(calibratedRed: 82.0 / 255.0, green: 92.0 / 255.0, blue: 107.0 / 255.0, alpha: 1)
            textTertiary = NSColor(calibratedRed: 110.0 / 255.0, green: 120.0 / 255.0, blue: 136.0 / 255.0, alpha: 1)
            textMuted = NSColor(calibratedRed: 134.0 / 255.0, green: 145.0 / 255.0, blue: 162.0 / 255.0, alpha: 1)
        }
    }
}

private struct Typography {
    let sidebarBrand = NSFont.systemFont(ofSize: 26, weight: .bold)
    let sidebarSection = NSFont.systemFont(ofSize: 11, weight: .medium)
    let sidebarIcon = NSFont.systemFont(ofSize: 12, weight: .medium)
    let sidebarItem = NSFont.systemFont(ofSize: 16, weight: .medium)

    let pageTitle = NSFont.systemFont(ofSize: 27, weight: .semibold)
    let joinWithURLTitle = NSFont.systemFont(ofSize: 17, weight: .semibold)
    let sectionTitleBold = NSFont.systemFont(ofSize: 25, weight: .bold)
    let dateHeading = NSFont.systemFont(ofSize: 18, weight: .medium)

    let tabIcon = NSFont.systemFont(ofSize: 13, weight: .regular)
    let tabTitle = NSFont.systemFont(ofSize: 31 / 2, weight: .semibold)

    let fieldLabel = NSFont.systemFont(ofSize: 15, weight: .medium)
    let inputPlaceholder = NSFont.systemFont(ofSize: 14, weight: .regular)
    let buttonText = NSFont.systemFont(ofSize: 16, weight: .medium)
    let filterText = NSFont.systemFont(ofSize: 15, weight: .regular)
    let filterArrow = NSFont.systemFont(ofSize: 12, weight: .regular)
    let iconButton = NSFont.systemFont(ofSize: 14, weight: .medium)

    let cardIcon = NSFont.systemFont(ofSize: 8, weight: .bold)
    let cardTitle = NSFont.systemFont(ofSize: 15, weight: .semibold)
    let cardSubtitle = NSFont.systemFont(ofSize: 13, weight: .bold)
    let cardTime = NSFont.systemFont(ofSize: 12, weight: .regular)
}

// MARK: - In-app browser (macOS WKWebView + chrome)
// Note: This target is AppKit/macOS. iOS would use WKWebView or SFSafariViewController; Android would use WebView or Custom Tabs.

private enum InAppBrowserURLPolicy: Equatable {
    case allowAll
    case whitelist(hostSuffixes: [String])
}

private func inAppBrowserURLAllowed(_ url: URL, policy: InAppBrowserURLPolicy) -> Bool {
    let scheme = (url.scheme ?? "").lowercased()
    if scheme == "about" { return true }
    guard scheme == "http" || scheme == "https" else { return false }
    guard let host = url.host?.lowercased() else { return false }
    switch policy {
    case .allowAll:
        return true
    case .whitelist(let suffixes):
        for suffix in suffixes {
            let s = suffix.lowercased()
            if host == s || host.hasSuffix("." + s) { return true }
        }
        return false
    }
}

private enum InAppBrowserWebKitSupport {
    static func makeWebViewConfiguration() -> WKWebViewConfiguration {
        let config = WKWebViewConfiguration()
        config.websiteDataStore = .default()
        config.preferences.javaScriptCanOpenWindowsAutomatically = true
        if #available(macOS 12.3, *) {
            config.preferences.isElementFullscreenEnabled = true
        }
        config.mediaTypesRequiringUserActionForPlayback = []
        if #available(macOS 11.0, *) {
            config.defaultWebpagePreferences.allowsContentJavaScript = true
        }
        config.applicationNameForUserAgent = "MeetingsApp/1.0"
        return config
    }
}

private final class InAppBrowserWindowController: NSWindowController {
    private static let defaultContentSize = NSSize(width: 1100, height: 760)
    private static let minimumContentSize = NSSize(width: 800, height: 520)

    private let browserViewController = InAppBrowserContainerViewController()

    init() {
        let browserWindow = NSWindow(
            contentRect: NSRect(origin: .zero, size: Self.defaultContentSize),
            styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
            backing: .buffered,
            defer: false
        )
        browserWindow.title = "Browser"
        browserWindow.titlebarAppearsTransparent = true
        browserWindow.titleVisibility = .hidden
        browserWindow.isRestorable = false
        browserWindow.setFrameAutosaveName("")
        browserWindow.minSize = browserWindow.frameRect(forContentRect: NSRect(origin: .zero, size: Self.minimumContentSize)).size
        browserWindow.center()
        browserWindow.contentViewController = browserViewController
        super.init(window: browserWindow)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        nil
    }

    /// Resets size and position each time the browser is shown so a previously tiny window is never reused.
    func applyDefaultFrameCenteredOnVisibleScreen() {
        guard let w = window, let screen = w.screen ?? NSScreen.main else { return }
        let windowFrame = w.frameRect(forContentRect: NSRect(origin: .zero, size: Self.defaultContentSize))
        let vf = screen.visibleFrame
        var frame = windowFrame
        frame.origin.x = vf.midX - frame.width / 2
        frame.origin.y = vf.midY - frame.height / 2
        if frame.maxX > vf.maxX { frame.origin.x = vf.maxX - frame.width }
        if frame.minX < vf.minX { frame.origin.x = vf.minX }
        if frame.maxY > vf.maxY { frame.origin.y = vf.maxY - frame.height }
        if frame.minY < vf.minY { frame.origin.y = vf.minY }
        w.setFrame(frame, display: true)
    }

    func load(url: URL, policy: InAppBrowserURLPolicy) {
        browserViewController.setNavigationPolicy(policy)
        browserViewController.load(url: url)
    }
}

private final class InAppBrowserContainerViewController: NSViewController, WKNavigationDelegate, WKUIDelegate, NSTextFieldDelegate {
    private var webView: WKWebView!
    private var webContainerView: NSView!
    private weak var urlField: NSTextField?
    private var backButton: NSButton!
    private var forwardButton: NSButton!
    private var reloadStopButton: NSButton!
    private var goButton: NSButton!
    private var progressBar: NSProgressIndicator!
    private weak var titlebarButtonsContainer: NSStackView?
    private weak var titlebarBackButton: NSButton?
    private weak var titlebarForwardButton: NSButton?
    private weak var titlebarReloadButton: NSButton?
    private weak var titlebarHomeButton: NSButton?

    private var lastLoadedURL: URL?
    private var navigationPolicy: InAppBrowserURLPolicy = .allowAll
    private var processTerminateRetryCount = 0
    /// Includes fresh WKWebView instances so each retry gets a new WebContent process after a crash.
    private let maxProcessTerminateRetries = 3
    private var kvoTokens: [NSKeyValueObservation] = []

    deinit {
        kvoTokens.removeAll()
    }

    func setNavigationPolicy(_ policy: InAppBrowserURLPolicy) {
        navigationPolicy = policy
    }

    override func loadView() {
        let root = NSView()
        root.translatesAutoresizingMaskIntoConstraints = false

        let wv = makeWebView()
        webView = wv

        let webHost = NSView()
        webHost.translatesAutoresizingMaskIntoConstraints = false
        webHost.wantsLayer = true
        webHost.addSubview(wv)
        NSLayoutConstraint.activate([
            wv.leadingAnchor.constraint(equalTo: webHost.leadingAnchor),
            wv.trailingAnchor.constraint(equalTo: webHost.trailingAnchor),
            wv.topAnchor.constraint(equalTo: webHost.topAnchor),
            wv.bottomAnchor.constraint(equalTo: webHost.bottomAnchor)
        ])
        webContainerView = webHost

        let toolbar = NSStackView()
        toolbar.translatesAutoresizingMaskIntoConstraints = false
        toolbar.orientation = .horizontal
        toolbar.spacing = 8
        toolbar.alignment = .centerY
        toolbar.edgeInsets = NSEdgeInsets(top: 6, left: 10, bottom: 6, right: 10)
        toolbar.isHidden = true

        backButton = makeToolbarButton(title: "◀", symbolName: "chevron.backward", accessibilityDescription: "Back")
        backButton.target = self
        backButton.action = #selector(goBack)
        forwardButton = makeToolbarButton(title: "▶", symbolName: "chevron.forward", accessibilityDescription: "Forward")
        forwardButton.target = self
        forwardButton.action = #selector(goForward)
        reloadStopButton = makeToolbarButton(title: "Reload", symbolName: "arrow.clockwise", accessibilityDescription: "Reload")
        reloadStopButton.target = self
        reloadStopButton.action = #selector(reloadOrStop)

        let field = NSTextField(string: "")
        field.translatesAutoresizingMaskIntoConstraints = false
        field.font = NSFont.systemFont(ofSize: 13, weight: .regular)
        field.placeholderString = "Address"
        field.cell?.sendsActionOnEndEditing = false
        field.delegate = self
        urlField = field

        goButton = NSButton(title: "Go", target: self, action: #selector(addressFieldSubmitted))
        goButton.translatesAutoresizingMaskIntoConstraints = false
        goButton.bezelStyle = .rounded

        toolbar.addArrangedSubview(backButton)
        toolbar.addArrangedSubview(forwardButton)
        toolbar.addArrangedSubview(reloadStopButton)
        toolbar.addArrangedSubview(field)
        toolbar.addArrangedSubview(goButton)
        field.widthAnchor.constraint(greaterThanOrEqualToConstant: 240).isActive = true
        toolbar.heightAnchor.constraint(equalToConstant: 0).isActive = true

        let bar = NSProgressIndicator()
        bar.translatesAutoresizingMaskIntoConstraints = false
        bar.style = .bar
        bar.isIndeterminate = false
        bar.minValue = 0
        bar.maxValue = 1
        bar.doubleValue = 0
        bar.isHidden = true
        progressBar = bar

        let separator = NSBox()
        separator.translatesAutoresizingMaskIntoConstraints = false
        separator.boxType = .separator

        webView.navigationDelegate = self
        webView.uiDelegate = self

        root.addSubview(toolbar)
        root.addSubview(bar)
        root.addSubview(separator)
        root.addSubview(webHost)

        NSLayoutConstraint.activate([
            toolbar.leadingAnchor.constraint(equalTo: root.leadingAnchor),
            toolbar.trailingAnchor.constraint(equalTo: root.trailingAnchor),
            toolbar.topAnchor.constraint(equalTo: root.safeAreaLayoutGuide.topAnchor),

            bar.leadingAnchor.constraint(equalTo: root.leadingAnchor),
            bar.trailingAnchor.constraint(equalTo: root.trailingAnchor),
            bar.topAnchor.constraint(equalTo: root.safeAreaLayoutGuide.topAnchor),
            bar.heightAnchor.constraint(equalToConstant: 3),

            separator.leadingAnchor.constraint(equalTo: root.leadingAnchor),
            separator.trailingAnchor.constraint(equalTo: root.trailingAnchor),
            separator.topAnchor.constraint(equalTo: bar.bottomAnchor),

            webHost.leadingAnchor.constraint(equalTo: root.leadingAnchor),
            webHost.trailingAnchor.constraint(equalTo: root.trailingAnchor),
            webHost.topAnchor.constraint(equalTo: separator.bottomAnchor),
            webHost.bottomAnchor.constraint(equalTo: root.bottomAnchor)
        ])

        view = root
        installWebViewObservers()
        syncToolbarFromWebView()
    }

    override func viewDidAppear() {
        super.viewDidAppear()
        if let window = view.window {
            installTitlebarButtonsIfNeeded(on: window)
            syncWindowTitle()
            syncToolbarFromWebView()
        }
    }

    private func makeWebView() -> WKWebView {
        let wv = WKWebView(frame: .zero, configuration: InAppBrowserWebKitSupport.makeWebViewConfiguration())
        wv.translatesAutoresizingMaskIntoConstraints = false
        return wv
    }

    private func teardownWebViewObservers() {
        kvoTokens.removeAll()
    }

    /// New `WKWebView` = new WebContent process (helps after GPU/JS crashes on heavy sites like Meet).
    private func replaceWebViewAndLoad(url: URL) {
        teardownWebViewObservers()
        webView.navigationDelegate = nil
        webView.uiDelegate = nil
        webView.removeFromSuperview()

        let wv = makeWebView()
        webView = wv
        webContainerView.addSubview(wv)
        NSLayoutConstraint.activate([
            wv.leadingAnchor.constraint(equalTo: webContainerView.leadingAnchor),
            wv.trailingAnchor.constraint(equalTo: webContainerView.trailingAnchor),
            wv.topAnchor.constraint(equalTo: webContainerView.topAnchor),
            wv.bottomAnchor.constraint(equalTo: webContainerView.bottomAnchor)
        ])
        webView.navigationDelegate = self
        webView.uiDelegate = self
        installWebViewObservers()
        syncToolbarFromWebView()
        webView.load(URLRequest(url: url, cachePolicy: .reloadIgnoringLocalAndRemoteCacheData))
    }

    private func makeToolbarButton(title: String, symbolName: String, accessibilityDescription: String) -> NSButton {
        let b = NSButton()
        b.translatesAutoresizingMaskIntoConstraints = false
        b.bezelStyle = .texturedRounded
        b.setAccessibilityLabel(accessibilityDescription)
        if #available(macOS 11.0, *), let img = NSImage(systemSymbolName: symbolName, accessibilityDescription: accessibilityDescription) {
            b.image = img
            b.imagePosition = .imageOnly
        } else {
            b.title = title
        }
        b.widthAnchor.constraint(greaterThanOrEqualToConstant: 32).isActive = true
        return b
    }

    private func installWebViewObservers() {
        kvoTokens.append(webView.observe(\.canGoBack, options: [.new]) { [weak self] _, _ in
            self?.syncToolbarFromWebView()
        })
        kvoTokens.append(webView.observe(\.canGoForward, options: [.new]) { [weak self] _, _ in
            self?.syncToolbarFromWebView()
        })
        kvoTokens.append(webView.observe(\.isLoading, options: [.new]) { [weak self] _, _ in
            self?.syncToolbarFromWebView()
        })
        kvoTokens.append(webView.observe(\.estimatedProgress, options: [.new]) { [weak self] _, _ in
            self?.syncProgressFromWebView()
        })
        kvoTokens.append(webView.observe(\.title, options: [.new]) { [weak self] _, _ in
            self?.syncWindowTitle()
        })
        kvoTokens.append(webView.observe(\.url, options: [.new]) { [weak self] _, _ in
            self?.syncAddressFieldFromWebView()
        })
    }

    private func syncToolbarFromWebView() {
        backButton?.isEnabled = webView.canGoBack
        forwardButton?.isEnabled = webView.canGoForward
        titlebarBackButton?.isEnabled = webView.canGoBack
        titlebarForwardButton?.isEnabled = webView.canGoForward
        if webView.isLoading {
            if #available(macOS 11.0, *), let img = NSImage(systemSymbolName: "xmark", accessibilityDescription: "Stop") {
                reloadStopButton.image = img
                reloadStopButton.imagePosition = .imageOnly
                reloadStopButton.title = ""
                titlebarReloadButton?.image = img
                titlebarReloadButton?.imagePosition = .imageOnly
                titlebarReloadButton?.title = ""
            } else {
                reloadStopButton.title = "Stop"
                titlebarReloadButton?.title = "Stop"
            }
        } else {
            if #available(macOS 11.0, *), let img = NSImage(systemSymbolName: "arrow.clockwise", accessibilityDescription: "Reload") {
                reloadStopButton.image = img
                reloadStopButton.imagePosition = .imageOnly
                reloadStopButton.title = ""
                titlebarReloadButton?.image = img
                titlebarReloadButton?.imagePosition = .imageOnly
                titlebarReloadButton?.title = ""
            } else {
                reloadStopButton.title = "Reload"
                titlebarReloadButton?.title = "Reload"
            }
        }
        syncProgressFromWebView()
    }

    private func syncProgressFromWebView() {
        guard let progressBar else { return }
        if webView.isLoading {
            progressBar.isHidden = false
            progressBar.doubleValue = webView.estimatedProgress
        } else {
            progressBar.isHidden = true
            progressBar.doubleValue = 0
        }
    }

    private func syncAddressFieldFromWebView() {
        guard let urlField, urlField.currentEditor() == nil, let url = webView.url else { return }
        urlField.stringValue = url.absoluteString
    }

    private func syncWindowTitle() {
        let t = webView.title?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        let host = webView.url?.host ?? ""
        let title = t.isEmpty ? (host.isEmpty ? "Browser" : host) : t
        view.window?.title = title
    }

    private func installTitlebarButtonsIfNeeded(on window: NSWindow) {
        guard titlebarButtonsContainer == nil else { return }
        guard let titlebarView = window.standardWindowButton(.closeButton)?.superview else { return }
        guard let zoomButton = window.standardWindowButton(.zoomButton) else { return }

        let stack = NSStackView()
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.orientation = .horizontal
        stack.alignment = .centerY
        stack.spacing = 6

        let back = makeToolbarButton(title: "◀", symbolName: "chevron.backward", accessibilityDescription: "Back")
        back.target = self
        back.action = #selector(goBack)
        let forward = makeToolbarButton(title: "▶", symbolName: "chevron.forward", accessibilityDescription: "Forward")
        forward.target = self
        forward.action = #selector(goForward)
        let reload = makeToolbarButton(title: "Reload", symbolName: "arrow.clockwise", accessibilityDescription: "Reload")
        reload.target = self
        reload.action = #selector(reloadOrStop)
        let home = makeToolbarButton(title: "Home", symbolName: "house", accessibilityDescription: "Home")
        home.target = self
        home.action = #selector(goHome)

        stack.addArrangedSubview(back)
        stack.addArrangedSubview(forward)
        stack.addArrangedSubview(reload)
        stack.addArrangedSubview(home)
        titlebarView.addSubview(stack)

        NSLayoutConstraint.activate([
            stack.leadingAnchor.constraint(equalTo: zoomButton.trailingAnchor, constant: 12),
            stack.centerYAnchor.constraint(equalTo: zoomButton.centerYAnchor)
        ])

        titlebarButtonsContainer = stack
        titlebarBackButton = back
        titlebarForwardButton = forward
        titlebarReloadButton = reload
        titlebarHomeButton = home
    }

    func load(url: URL) {
        lastLoadedURL = url
        processTerminateRetryCount = 0
        urlField?.stringValue = url.absoluteString
        webView.load(URLRequest(url: url))
        syncWindowTitle()
    }

    @objc private func goBack() {
        webView.goBack()
    }

    @objc private func goForward() {
        webView.goForward()
    }

    @objc private func reloadOrStop() {
        if webView.isLoading {
            webView.stopLoading()
        } else {
            webView.reload()
        }
    }

    @objc private func goHome() {
        guard let homeURL = URL(string: "https://classroom.google.com/") else { return }
        load(url: homeURL)
    }

    @objc private func addressFieldSubmitted() {
        let raw = urlField?.stringValue.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        guard raw.isEmpty == false else { return }
        var normalized = raw
        if normalized.lowercased().hasPrefix("http://") == false && normalized.lowercased().hasPrefix("https://") == false {
            normalized = "https://\(normalized)"
        }
        guard let url = URL(string: normalized),
              let scheme = url.scheme?.lowercased(),
              scheme == "http" || scheme == "https",
              url.host != nil
        else {
            let alert = NSAlert()
            alert.messageText = "Invalid address"
            alert.informativeText = "Enter a valid web address, for example https://example.com"
            alert.addButton(withTitle: "OK")
            alert.runModal()
            return
        }
        guard inAppBrowserURLAllowed(url, policy: navigationPolicy) else {
            presentBlockedHostAlert()
            return
        }
        load(url: url)
    }

    private func presentBlockedHostAlert() {
        let alert = NSAlert()
        alert.messageText = "Address not allowed"
        alert.informativeText = "This URL is not permitted with the current in-app browser policy (whitelist)."
        alert.addButton(withTitle: "OK")
        alert.runModal()
    }

    private func openExternally(_ url: URL) {
        NSWorkspace.shared.open(url)
    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        processTerminateRetryCount = 0
        syncAddressFieldFromWebView()
        syncWindowTitle()
    }

    func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) {
        let nsError = error as NSError
        if nsError.code == NSURLErrorCancelled {
            return
        }
        let alert = NSAlert()
        alert.messageText = "Unable to load page"
        alert.informativeText = "Could not load this page in the in-app browser.\n\n\(error.localizedDescription)"
        alert.addButton(withTitle: "Try Again")
        alert.addButton(withTitle: "OK")
        if alert.runModal() == .alertFirstButtonReturn, let url = lastLoadedURL {
            processTerminateRetryCount = 0
            webView.load(URLRequest(url: url))
        }
    }

    func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
        guard let url = lastLoadedURL else { return }

        if processTerminateRetryCount < maxProcessTerminateRetries {
            processTerminateRetryCount += 1
            replaceWebViewAndLoad(url: url)
            return
        }

        let alert = NSAlert()
        alert.messageText = "Page stopped loading"
        alert.informativeText =
            "The in-app browser closed this page unexpectedly. You can try loading it again in this same window."
        alert.addButton(withTitle: "Try Again")
        alert.addButton(withTitle: "OK")
        if alert.runModal() == .alertFirstButtonReturn {
            processTerminateRetryCount = 0
            replaceWebViewAndLoad(url: url)
        }
    }

    func webView(
        _ webView: WKWebView,
        decidePolicyFor navigationAction: WKNavigationAction,
        decisionHandler: @escaping (WKNavigationActionPolicy) -> Void
    ) {
        guard let url = navigationAction.request.url else {
            decisionHandler(.allow)
            return
        }
        let scheme = (url.scheme ?? "").lowercased()
        if scheme != "http" && scheme != "https" {
            openExternally(url)
            decisionHandler(.cancel)
            return
        }
        if inAppBrowserURLAllowed(url, policy: navigationPolicy) == false {
            if navigationAction.targetFrame?.isMainFrame != false {
                DispatchQueue.main.async { [weak self] in
                    self?.presentBlockedHostAlert()
                }
            }
            decisionHandler(.cancel)
            return
        }
        decisionHandler(.allow)
    }

    func webView(
        _ webView: WKWebView,
        createWebViewWith configuration: WKWebViewConfiguration,
        for navigationAction: WKNavigationAction,
        windowFeatures: WKWindowFeatures
    ) -> WKWebView? {
        if navigationAction.targetFrame == nil, let requestURL = navigationAction.request.url {
            let scheme = (requestURL.scheme ?? "").lowercased()
            if scheme != "http" && scheme != "https" {
                openExternally(requestURL)
            } else if inAppBrowserURLAllowed(requestURL, policy: navigationPolicy) {
                webView.load(URLRequest(url: requestURL))
            } else {
                presentBlockedHostAlert()
            }
        }
        return nil
    }

    func control(_ control: NSControl, textView: NSTextView, doCommandBy commandSelector: Selector) -> Bool {
        if control === urlField, commandSelector == #selector(NSResponder.insertNewline(_:)) {
            addressFieldSubmitted()
            return true
        }
        return false
    }
}