macos-design-guidelines

SKILL.md

macOS Human Interface Guidelines

Mac apps serve power users who expect deep keyboard control, persistent menu bars, resizable multi-window layouts, and tight system integration. These guidelines codify Apple's HIG into actionable rules with SwiftUI and AppKit examples.

1. Menu Bar (CRITICAL)

Every Mac app must have a menu bar. It is the primary discovery mechanism for commands. Users who cannot find a feature will look in the menu bar before anywhere else.

Rule 1.1 — Provide Standard Menus

Every app must include at minimum: App, File, Edit, View, Window, Help. Omit File only if the app is not document-based. Add app-specific menus between Edit and View or between View and Window.
// SwiftUI — Standard menu structure
@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .commands {
            // Adds to existing standard menus
            CommandGroup(after: .newItem) {
                Button("New from Template...") { newFromTemplate() }
                    .keyboardShortcut("T", modifiers: [.command, .shift])
            }
            CommandMenu("Canvas") {
                Button("Zoom to Fit") { zoomToFit() }
                    .keyboardShortcut("0", modifiers: .command)
                Divider()
                Button("Add Artboard") { addArtboard() }
                    .keyboardShortcut("A", modifiers: [.command, .shift])
            }
        }
    }
}

// AppKit — Building menus programmatically
let editMenu = NSMenu(title: "Edit")
let undoItem = NSMenuItem(title: "Undo", action: #selector(UndoManager.undo), keyEquivalent: "z")
let redoItem = NSMenuItem(title: "Redo", action: #selector(UndoManager.redo), keyEquivalent: "Z")
editMenu.addItem(undoItem)
editMenu.addItem(redoItem)
editMenu.addItem(.separator())

Rule 1.2 — Keyboard Shortcuts for All Menu Items

Every menu item that performs an action must have a keyboard shortcut. Use standard shortcuts for standard actions (Cmd+C, Cmd+V, Cmd+Z, etc.). Custom shortcuts should use Cmd plus a letter. Reserve Cmd+Shift, Cmd+Option, and Cmd+Ctrl combos for secondary actions.

Standard Shortcut Reference:

Action
Shortcut

New
Cmd+N

Open
Cmd+O

Close
Cmd+W

Save
Cmd+S

Save As
Cmd+Shift+S

Print
Cmd+P

Undo
Cmd+Z

Redo
Cmd+Shift+Z

Cut
Cmd+X

Copy
Cmd+C

Paste
Cmd+V

Select All
Cmd+A

Find
Cmd+F

Find Next
Cmd+G

Preferences/Settings
Cmd+,

Hide App
Cmd+H

Quit
Cmd+Q

Minimize
Cmd+M

Fullscreen
Cmd+Ctrl+F

Rule 1.3 — Dynamic Menu Updates

Menu items must reflect current state. Disable items that are not applicable. Update titles to match context (e.g., "Undo Typing" not just "Undo"). Toggle checkmarks for on/off states.

// SwiftUI — Add sidebar toggle alongside existing toolbar menu commands
CommandGroup(after: .toolbar) {
    Button(showingSidebar ? "Hide Sidebar" : "Show Sidebar") {
        showingSidebar.toggle()
    }
    .keyboardShortcut("S", modifiers: [.command, .control])
}

// AppKit — Validate menu items
override func validateMenuItem(_ menuItem: NSMenuItem) -> Bool {
    if menuItem.action == #selector(delete(_:)) {
        menuItem.title = selectedItems.count > 1 ? "Delete \(selectedItems.count) Items" : "Delete"
        return !selectedItems.isEmpty
    }
    return super.validateMenuItem(menuItem)
}

Rule 1.4 — Contextual Menus

Provide right-click context menus on all interactive elements. Context menus should contain the most relevant subset of menu bar actions for the clicked element, plus element-specific actions.

// SwiftUI
Text(item.name)
    .contextMenu {
        Button("Rename...") { rename(item) }
        Button("Duplicate") { duplicate(item) }
        Divider()
        Button("Delete", role: .destructive) { delete(item) }
    }

Rule 1.5 — App Menu Structure

The App menu (leftmost, bold app name) must contain: About, Preferences/Settings (Cmd+,), Services submenu, Hide App (Cmd+H), Hide Others (Cmd+Option+H), Show All, Quit (Cmd+Q). Never rename or remove these standard items.

// SwiftUI — Settings scene
@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup { ContentView() }
        Settings { SettingsView() }  // Automatically wired to Cmd+,
    }
}

Rule 1.6 — Stable Command Names and Locations

Treat the menu bar as the app's command memory. Keep common actions in consistent menus with stable names and shortcuts so users recognize them quickly instead of searching for context-specific variants.

2. Windows (CRITICAL)

Mac users expect full control over window size, position, and lifecycle. An app that fights window management feels fundamentally broken on the Mac.

Rule 2.1 — Resizable with Sensible Minimums

All main windows must be freely resizable. Set a minimum size that keeps the UI usable. Never set a maximum size unless the content truly cannot scale (rare).

// SwiftUI
WindowGroup {
    ContentView()
        .frame(minWidth: 600, minHeight: 400)
}
.defaultSize(width: 900, height: 600)

// AppKit
window.minSize = NSSize(width: 600, height: 400)
window.setContentSize(NSSize(width: 900, height: 600))

Rule 2.2 — Support Fullscreen and Split View

Opt into native fullscreen by setting the appropriate window collection behavior. The green traffic-light button must either enter fullscreen or show the tile picker.

// AppKit
window.collectionBehavior.insert(.fullScreenPrimary)

SwiftUI windows get fullscreen support automatically.

Rule 2.3 — Multiple Windows

Unless your app is a single-purpose utility, support multiple windows. Document-based apps must allow multiple documents open simultaneously. Use WindowGroup or DocumentGroup in SwiftUI.

// SwiftUI — Document-based app
@main
struct TextEditorApp: App {
    var body: some Scene {
        DocumentGroup(newDocument: TextDocument()) { file in
            TextEditorView(document: file.$document)
        }
    }
}

Rule 2.4 — Title Bar Shows Document Info

For document-based apps, the title bar must show the document name. Support proxy icon dragging. Show edited state (dot in close button). Support title bar renaming on click.

// AppKit
window.representedURL = document.fileURL
window.title = document.displayName
window.isDocumentEdited = document.hasUnsavedChanges

// SwiftUI — NavigationSplitView titles
NavigationSplitView {
    SidebarView()
} detail: {
    DetailView()
        .navigationTitle(document.name)
}

Rule 2.5 — Remember Window State

Persist window position, size, and state across launches. Use NSWindow.setFrameAutosaveName or SwiftUI's built-in state restoration.

// AppKit
window.setFrameAutosaveName("MainWindow")

// SwiftUI — Automatic with WindowGroup
WindowGroup(id: "main") {
    ContentView()
}
.defaultPosition(.center)

Rule 2.6 — Traffic Light Buttons

Never hide or reposition the close (red), minimize (yellow), or zoom (green) buttons. They must remain in the top-left corner. If using a custom title bar, the buttons must still be visible and functional.

// AppKit — Custom title bar that preserves traffic lights
window.titlebarAppearsTransparent = true
window.styleMask.insert(.fullSizeContentView)
// Traffic lights remain functional and visible

3. Toolbars (HIGH)

Toolbars are the secondary command surface after the menu bar. They provide quick access to frequent actions and should be customizable.

Rule 3.1 — Unified Title Bar and Toolbar

Use the unified title bar + toolbar style for a modern appearance. The toolbar sits in the title bar area, saving vertical space.

// SwiftUI
WindowGroup {
    ContentView()
        .toolbar {
            ToolbarItem(placement: .primaryAction) {
                Button(action: compose) {
                    Label("Compose", systemImage: "square.and.pencil")
                }
            }
        }
}
.windowToolbarStyle(.unified)

// AppKit
window.titleVisibility = .hidden
window.toolbarStyle = .unified

Rule 3.2 — User-Customizable Toolbars

Allow users to add, remove, and rearrange toolbar items. Provide a default set and a superset of available items.

// SwiftUI — Customizable toolbar
.toolbar(id: "main") {
    ToolbarItem(id: "compose", placement: .primaryAction) {
        Button(action: compose) {
            Label("Compose", systemImage: "square.and.pencil")
        }
    }
    ToolbarItem(id: "filter", placement: .secondaryAction) {
        Button(action: toggleFilter) {
            Label("Filter", systemImage: "line.3.horizontal.decrease")
        }
    }
}
.toolbarRole(.editor)

Rule 3.3 — Segmented Controls for View Switching

Use a segmented control or picker in the toolbar for switching between content views (e.g., List/Grid/Column). This is a toolbar pattern, not a tab bar.

// SwiftUI
ToolbarItem(placement: .principal) {
    Picker("View Mode", selection: $viewMode) {
        Label("List", systemImage: "list.bullet").tag(ViewMode.list)
        Label("Grid", systemImage: "square.grid.2x2").tag(ViewMode.grid)
        Label("Column", systemImage: "rectangle.split.3x1").tag(ViewMode.column)
    }
    .pickerStyle(.segmented)
}

Rule 3.4 — Search Field in Toolbar

Place the search field in the trailing area of the toolbar. Use .searchable() in SwiftUI for standard search behavior with suggestions and tokens.

// SwiftUI
NavigationSplitView {
    SidebarView()
} detail: {
    ContentListView()
        .searchable(text: $searchText, placement: .toolbar, prompt: "Search items")
        .searchSuggestions {
            ForEach(suggestions) { suggestion in
                Text(suggestion.title).searchCompletion(suggestion.title)
            }
        }
}

Rule 3.5 — Toolbar Labels and Icons

Toolbar items should have both an icon (SF Symbol) and a text label. In compact mode, show icons only. Prefer labeled icons for discoverability. Use Label to supply both.

4. Sidebars (HIGH)

Sidebars are the primary navigation surface for Mac apps. They appear on the leading edge and provide persistent access to top-level sections and content libraries.

Rule 4.1 — Leading Edge, Collapsible

Place the sidebar on the left (leading) edge. Make it collapsible via the toolbar button or a keyboard shortcut. Apple does not define a universal sidebar shortcut — choose one appropriate for your app (e.g., Cmd+Ctrl+S is common but not guaranteed to be free in all apps). Persist collapsed state.

// SwiftUI
NavigationSplitView(columnVisibility: $columnVisibility) {
    List(selection: $selection) {
        Section("Library") {
            Label("All Items", systemImage: "tray.full")
            Label("Favorites", systemImage: "star")
            Label("Recent", systemImage: "clock")
        }
        Section("Tags") {
            ForEach(tags) { tag in
                Label(tag.name, systemImage: "tag")
            }
        }
    }
    .navigationSplitViewColumnWidth(min: 180, ideal: 220, max: 320)
} detail: {
    DetailView(selection: selection)
}
.navigationSplitViewStyle(.prominentDetail)

Rule 4.2 — Source List Style

Use the source list style (.listStyle(.sidebar)) for content-library navigation. Source lists have a translucent background that shows the desktop or window behind them with vibrancy effects.

// SwiftUI
List(selection: $selection) {
    ForEach(sections) { section in
        Section(section.name) {
            ForEach(section.items) { item in
                NavigationLink(value: item) {
                    Label(item.name, systemImage: item.icon)
                }
            }
        }
    }
}
.listStyle(.sidebar)

Rule 4.3 — Outline Views for Hierarchies

When content is hierarchical (e.g., folder trees, project structures), use disclosure groups or outline views to let users expand and collapse levels.

// SwiftUI — Recursive outline
List(selection: $selection) {
    OutlineGroup(rootNodes, children: \.children) { node in
        Label(node.name, systemImage: node.icon)
    }
}

Rule 4.4 — Drag to Reorder

Sidebar items that can be reordered (bookmarks, favorites, custom sections) must support drag-to-reorder. Implement onMove or NSOutlineView drag delegates.

// SwiftUI
ForEach(favorites) { item in
    Label(item.name, systemImage: item.icon)
}
.onMove { source, destination in
    favorites.move(fromOffsets: source, toOffset: destination)
}

Rule 4.5 — Badge Counts

Show badge counts on sidebar items for unread counts, pending items, or notifications. Use the .badge() modifier.

// SwiftUI
Label("Inbox", systemImage: "tray")
    .badge(unreadCount)

5. Keyboard (CRITICAL)

Mac users rely on keyboard shortcuts more than any other platform. An app without comprehensive keyboard support is a broken Mac app.

Rule 5.1 — Cmd Shortcuts for Everything

Every action reachable by mouse must have a keyboard equivalent. Primary actions use Cmd+letter. Secondary actions use Cmd+Shift or Cmd+Option. Tertiary actions use Cmd+Ctrl.

Keyboard Shortcut Conventions:

Modifier Pattern
Usage

Cmd+letter
Primary actions (New, Open, Save, etc.)

Cmd+Shift+letter
Variant of primary (Save As, Find Previous)

Cmd+Option+letter
Alternative mode (Paste and Match Style)

Cmd+Ctrl+letter
Window/view controls (Fullscreen, Sidebar)

Ctrl+letter
Emacs-style text navigation (acceptable)

Fn+key
System functions (F11 Show Desktop, etc.)

Rule 5.2 — Full Keyboard Navigation

Support Tab to move between controls. Support arrow keys within lists, grids, and tables. Support Shift+Tab for reverse navigation. Use focusable() and @FocusState in SwiftUI.

// SwiftUI — Focus management
struct ContentView: View {
    @FocusState private var focusedField: Field?

    var body: some View {
        VStack {
            TextField("Name", text: $name)
                .focused($focusedField, equals: .name)
            TextField("Email", text: $email)
                .focused($focusedField, equals: .email)
        }
        .onSubmit { advanceFocus() }
    }
}

Rule 5.3 — Escape to Cancel or Close

Esc must dismiss popovers, sheets, dialogs, and cancel in-progress operations. In text fields, Esc reverts to the previous value. In modal dialogs, Esc is equivalent to clicking Cancel.

// SwiftUI — Sheet with Esc support (automatic)
.sheet(isPresented: $showingSheet) {
    SheetView()  // Esc dismisses automatically
}

// AppKit — Custom responder
override func cancelOperation(_ sender: Any?) {
    dismiss(nil)
}

Rule 5.4 — Return for Default Action

In dialogs and forms, Return/Enter activates the default button (visually emphasized in blue). The default button is always the safest primary action.

// SwiftUI
Button("Save") { save() }
    .keyboardShortcut(.defaultAction)  // Enter key

Button("Cancel") { cancel() }
    .keyboardShortcut(.cancelAction)   // Esc key

Rule 5.5 — Delete for Removal

The Delete key (Backspace) must remove selected items in lists, tables, and collections. Cmd+Delete for more destructive removal (move to Trash). Always support Cmd+Z to undo deletion.

Rule 5.6 — Space for Quick Look

When items support previewing, Space bar should invoke Quick Look. Use the QLPreviewPanel API in AppKit or .quickLookPreview() in SwiftUI.

// SwiftUI
List(selection: $selection) {
    ForEach(files) { file in
        FileRow(file: file)
    }
}
.quickLookPreview($quickLookItem, in: files)

Rule 5.7 — Arrow Key Navigation

In lists and grids, Up/Down arrow keys move selection. Left/Right collapse/expand disclosure groups or navigate columns. Cmd+Up goes to the beginning, Cmd+Down goes to the end.

6. Pointer and Mouse (HIGH)

Mac is a pointer-driven platform. Every interactive element must respond to hover, click, right-click, and drag.

Rule 6.1 — Hover States

All interactive elements must have a visible hover state. Buttons highlight, rows show a selection indicator, links change cursor. Use .onHover in SwiftUI.

// SwiftUI — Hover effect
struct HoverableRow: View {
    @State private var isHovered = false

    var body: some View {
        HStack {
            Text(item.name)
            Spacer()
            if isHovered {
                Button("Edit") { edit() }
                    .buttonStyle(.borderless)
            }
        }
        .padding(8)
        .background(isHovered ? Color.primary.opacity(0.05) : .clear)
        .cornerRadius(6)
        .onHover { hovering in isHovered = hovering }
    }
}

Rule 6.2 — Right-Click Context Menus

Every interactive element must respond to right-click with a contextual menu. The context menu should contain the most relevant actions for the clicked item.

Rule 6.3 — Drag and Drop

Support drag and drop for content manipulation: reordering items, moving between containers, importing files from Finder, and exporting content.

// SwiftUI — Drag and drop
ForEach(items) { item in
    ItemView(item: item)
        .draggable(item)
}
.dropDestination(for: Item.self) { items, location in
    handleDrop(items, at: location)
    return true
}

// Accepting file drops from Finder
.dropDestination(for: URL.self) { urls, location in
    importFiles(urls)
    return true
}

Rule 6.4 — Scroll Behavior

Support both trackpad (smooth/inertial) and mouse wheel (discrete) scrolling. Use elastic/bounce scrolling at content boundaries. Support horizontal scrolling where appropriate.

Rule 6.5 — Cursor Changes

Change the cursor to indicate affordances: pointer for clickable elements, I-beam for text, crosshair for drawing, resize handles at window/splitter edges, grab hand for draggable content.

// AppKit — Custom cursor
override func resetCursorRects() {
    addCursorRect(bounds, cursor: .crosshair)
}

Rule 6.6 — Multi-Selection

Support Cmd+Click for non-contiguous selection and Shift+Click for range selection in lists, tables, and grids. This is a deeply ingrained Mac interaction pattern.

// SwiftUI — Tables with multi-selection
Table(items, selection: $selectedItems) {
    TableColumn("Name", value: \.name)
    TableColumn("Date", value: \.dateFormatted)
    TableColumn("Size", value: \.sizeFormatted)
}

7. Notifications and Alerts (MEDIUM)

Mac users are protective of their attention. Only interrupt when truly necessary.

Rule 7.1 — Use Notification Center Appropriately

Send notifications only for events that happen outside the app or require user action. Never notify for routine operations. Notifications must be actionable.

// UserNotifications
let content = UNMutableNotificationContent()
content.title = "Download Complete"
content.body = "project-assets.zip is ready"
content.categoryIdentifier = "DOWNLOAD"
content.sound = .default

let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: nil)
UNUserNotificationCenter.current().add(request)

Rule 7.2 — Alerts with Suppression Option

For recurring alerts, provide a "Do not show this again" checkbox. Respect the user's choice and persist it.

// AppKit — Alert with suppression
let alert = NSAlert()
alert.messageText = "Remove from library?"
alert.informativeText = "The file will be moved to the Trash."
alert.alertStyle = .warning
alert.addButton(withTitle: "Remove")
alert.addButton(withTitle: "Cancel")
alert.showsSuppressionButton = true
alert.suppressionButton?.title = "Do not ask again"

let response = alert.runModal()
if alert.suppressionButton?.state == .on {
    UserDefaults.standard.set(true, forKey: "suppressRemoveAlert")
}

Rule 7.3 — Don't Interrupt Unnecessarily

Never show alerts for successful operations. Use inline status indicators, toolbar badges, or subtle animations instead. Reserve modal alerts for destructive or irreversible actions.

Rule 7.4 — Dock Badge

Show a badge on the Dock icon for notification counts. Clear it promptly when the user addresses the notifications.

// AppKit
NSApp.dockTile.badgeLabel = unreadCount > 0 ? "\(unreadCount)" : nil

Rule 7.5 — Match Feedback to Cognitive Cost

Routine actions should acknowledge completion with inline status, toolbar state, or a subtle animation. Use modal alerts only when the user must stop, evaluate consequences, and choose.

8. System Integration (MEDIUM)

Mac apps exist in a rich ecosystem. Deep integration makes an app feel native.

Rule 8.1 — Dock Icon and Menus

Provide a high-quality 1024x1024 app icon. Support Dock right-click menus for quick actions. Show recent documents in the Dock menu.

// AppKit — Dock menu
override func applicationDockMenu(_ sender: NSApplication) -> NSMenu? {
    let menu = NSMenu()
    menu.addItem(withTitle: "New Window", action: #selector(newWindow(_:)), keyEquivalent: "")
    menu.addItem(withTitle: "New Document", action: #selector(newDocument(_:)), keyEquivalent: "")
    menu.addItem(.separator())
    for doc in recentDocuments.prefix(5) {
        menu.addItem(withTitle: doc.name, action: #selector(openRecent(_:)), keyEquivalent: "")
    }
    return menu
}

Rule 8.2 — Spotlight Integration

Index app content for Spotlight search using CSSearchableItem and Core Spotlight. Users expect to find app content via Cmd+Space.

import CoreSpotlight

let attributeSet = CSSearchableItemAttributeSet(contentType: .text)
attributeSet.title = document.title
attributeSet.contentDescription = document.summary
attributeSet.thumbnailData = document.thumbnail?.pngData()

let item = CSSearchableItem(uniqueIdentifier: document.id, domainIdentifier: "documents", attributeSet: attributeSet)
CSSearchableIndex.default().indexSearchableItems([item])

Rule 8.3 — Quick Look Support

Provide Quick Look previews for custom file types via a Quick Look Preview Extension. Users expect Space to preview any file in Finder.

Rule 8.4 — Share Extensions

Implement the Share menu so users can share content from your app to Messages, Mail, Notes, etc. Also accept shared content from other apps.

// SwiftUI
ShareLink(item: document.url) {
    Label("Share", systemImage: "square.and.arrow.up")
}

Rule 8.5 — Services Menu

Register for the Services menu to receive text, URLs, or files from other apps. This is a uniquely Mac integration point that power users rely on.

Rule 8.6 — Shortcuts and AppleScript

Support the Shortcuts app by providing App Intents. For advanced automation, add AppleScript/JXA scripting support via an .sdef scripting dictionary.

// App Intents for Shortcuts
struct CreateDocumentIntent: AppIntent {
    static var title: LocalizedStringResource = "Create Document"
    static var description = IntentDescription("Creates a new document with the given title.")

    @Parameter(title: "Title")
    var title: String

    func perform() async throws -> some IntentResult {
        let doc = DocumentManager.shared.create(title: title)
        return .result(value: doc.title)
    }
}

9. Visual Design (HIGH)

Mac apps should look and feel like they belong on the platform. Use system-provided materials, fonts, and colors.

Rule 9.1 — Use System Fonts

Use SF Pro (the system font) at standard dynamic type sizes. Use SF Mono for code. Never hardcode font sizes; use semantic styles.

// SwiftUI — Semantic font styles
Text("Title").font(.title)
Text("Headline").font(.headline)
Text("Body text").font(.body)
Text("Caption").font(.caption)
Text("let x = 42").font(.system(.body, design: .monospaced))

Rule 9.2 — Vibrancy and Materials

Use system materials for sidebar and toolbar backgrounds. Vibrancy lets the desktop or underlying content show through, anchoring the app to the Mac visual language.

// SwiftUI
List { ... }
    .listStyle(.sidebar)  // Automatic vibrancy

// Custom vibrancy
ZStack {
    VisualEffectView(material: .sidebar, blendingMode: .behindWindow)
    Text("Sidebar Content")
}

// AppKit — Visual effect view
let visualEffect = NSVisualEffectView()
visualEffect.material = .sidebar
visualEffect.blendingMode = .behindWindow
visualEffect.state = .followsWindowActiveState

Rule 9.3 — Respect System Accent Color

Use the system accent color for selection, emphasis, and interactive elements. Never override it with a fixed brand color for standard controls. Use .accentColor or .tint only on custom views when appropriate.

// SwiftUI — Follows system accent automatically
Button("Action") { doSomething() }
    .buttonStyle(.borderedProminent)  // Uses system accent color

Toggle("Enable feature", isOn: $isEnabled)  // Toggle tint follows accent

Rule 9.4 — Support Dark Mode

Every view must support both Light and Dark appearances. Use semantic colors (Color.primary, Color.secondary, .background) rather than hardcoded colors. Test in both modes.

// SwiftUI — Semantic colors
Text("Title").foregroundStyle(.primary)
Text("Subtitle").foregroundStyle(.secondary)

RoundedRectangle(cornerRadius: 8)
    .fill(Color(nsColor: .controlBackgroundColor))

// Asset catalog: define colors for Both Appearances
// Never use Color.white or Color.black for UI surfaces

Rule 9.5 — Translucency

Respect the "Reduce transparency" accessibility setting. When transparency is reduced, replace translucent materials with solid backgrounds.

// SwiftUI
@Environment(\.accessibilityReduceTransparency) var reduceTransparency

var body: some View {
    if reduceTransparency {
        Color(nsColor: .windowBackgroundColor)
    } else {
        VisualEffectView(material: .sidebar, blendingMode: .behindWindow)
    }
}

Rule 9.6 — Consistent Spacing and Layout

Use 20pt standard margins, 8pt spacing between related controls, 20pt spacing between groups. Align controls to a grid. Use SwiftUI's built-in spacing or AppKit's Auto Layout with system spacing constraints.

10. Popovers (MEDIUM)

Popovers present contextual content anchored to a control. They are common in Mac apps for options panels, color pickers, and contextual settings.

Rule 10.1 — Use Popovers for Transient Context-Sensitive Content

Popovers attach to a source view and are dismissed by clicking outside or pressing Esc. Use them for settings or options that apply to a specific element. Do not use popovers for primary workflows or multi-step operations.

// SwiftUI
Button("Format...") { showingFormatPopover = true }
    .popover(isPresented: $showingFormatPopover, arrowEdge: .bottom) {
        FormatOptionsView()
            .frame(width: 280)
            .padding()
    }

Rule 10.2 — Dismiss Popovers with Esc

Popovers must close when the user presses Esc. SwiftUI handles this automatically for .popover. AppKit's NSPopover also dismisses on Esc when behavior is set to .transient or .semitransient.

Rule 10.3 — Size Popovers to Their Content

Set a reasonable width for the popover's content. Do not let the popover be wider than necessary. Content should not require scrolling unless the list is inherently long (e.g., a font picker).

11. Accessibility (CRITICAL)

Mac apps must support VoiceOver, Full Keyboard Access, Switch Control, and related assistive technologies.

Rule 11.1 — VoiceOver Labels on All Interactive Elements

Every button, control, and interactive element must have a meaningful accessibility label. Icon-only toolbar items and image buttons must provide labels.

Correct:

Button(action: deleteSelected) {
    Image(systemName: "trash")
}
.accessibilityLabel("Delete selected items")

Incorrect:

Button(action: deleteSelected) {
    Image(systemName: "trash")
}
// VoiceOver reads "trash" — ambiguous without context

Rule 11.2 — Full Keyboard Access

Every action reachable by mouse must also be reachable by keyboard. Tab must move focus between all controls. Arrow keys must navigate within lists, tables, and grids. No keyboard traps.

// SwiftUI — Ensure all custom views are focusable
MyCustomControl()
    .focusable()
    .onKeyPress(.return) { handleActivation(); return .handled }

Rule 11.3 — Respect Reduce Motion

Disable or substitute decorative animations when the user enables Reduce Motion.

@Environment(\.accessibilityReduceMotion) var reduceMotion

var body: some View {
    ContentView()
        .animation(reduceMotion ? nil : .spring(), value: isExpanded)
}

Rule 11.4 — Respect Reduce Transparency

Replace translucent materials with solid backgrounds when Reduce Transparency is enabled (see Rule 9.5).

Rule 11.5 — Logical Focus Order

VoiceOver must traverse elements in a logical reading order (top-left to bottom-right for LTR). Use .accessibilitySortPriority() or accessibilityElement(children:) to correct order when the visual layout diverges.

Rule 11.6 — Respond to Bold Text

When the user enables Bold Text in System Settings, custom-rendered text must adapt. SwiftUI text styles handle this automatically. For AppKit, check NSWorkspace.shared.accessibilityDisplayShouldUseBoldText, or use @Environment(\.legibilityWeight) in SwiftUI to apply heavier weights to custom text.

Correct:

// SwiftUI — environment handles bold text automatically for standard styles
Text("Section Header")
    .font(.headline)

// SwiftUI — custom rendering responds to legibilityWeight
@Environment(\.legibilityWeight) var legibilityWeight

var body: some View {
    Text("Custom Label")
        .fontWeight(legibilityWeight == .bold ? .bold : .regular)
}

Incorrect:

// Hardcoded weight ignores Bold Text preference
Text("Custom Label")
    .fontWeight(.regular) // Never adapts to Bold Text setting

Rule 11.7 — Respond to Increase Contrast

When the user enables Increase Contrast in System Settings, custom colors must provide higher-contrast variants. Use NSWorkspace.shared.accessibilityDisplayShouldIncreaseContrast in AppKit, or @Environment(\.colorSchemeContrast) in SwiftUI to detect and apply appropriate values.

Correct:

// SwiftUI
@Environment(\.colorSchemeContrast) var contrast

var borderColor: Color {
    contrast == .increased ? Color.primary : Color.secondary
}

// AppKit
let shouldIncrease = NSWorkspace.shared.accessibilityDisplayShouldIncreaseContrast
let borderColor: NSColor = shouldIncrease ? .labelColor : .separatorColor

Incorrect:

// Static color ignores Increase Contrast setting
let borderColor = NSColor.separatorColor // Always low-contrast; ignores user preference

Keyboard Shortcut Quick Reference

Navigation

Shortcut
Action

Cmd+N
New window/document

Cmd+O
Open

Cmd+W
Close window/tab

Cmd+Q
Quit app

Cmd+,
Settings/Preferences

Cmd+Tab
Switch apps

Cmd+`
Switch windows within app

Cmd+T
New tab

Editing

Shortcut
Action

Cmd+Z
Undo

Cmd+Shift+Z
Redo

Cmd+X / C / V
Cut / Copy / Paste

Cmd+A
Select All

Cmd+D
Duplicate

Cmd+F
Find

Cmd+G
Find Next

Cmd+Shift+G
Find Previous

Cmd+E
Use Selection for Find

View

Shortcut
Action

Cmd+Ctrl+F
Toggle fullscreen

Cmd+Ctrl+S
Toggle sidebar (app-defined; not a universal HIG standard)

Cmd++ / Cmd+-
Zoom in/out

Cmd+0
Actual size

Evaluation Checklist

Before shipping a Mac app, verify:

Menu Bar

 App has a complete menu bar with standard menus

 All actions have keyboard shortcuts

 Menu items dynamically update (enable/disable, title changes)

 Context menus on all interactive elements

 App menu has About, Settings, Hide, Quit

Windows

 Windows are freely resizable with sensible minimums

 Fullscreen and Split View work

 Multiple windows supported (if appropriate)

 Window position and size persist across launches

 Traffic light buttons visible and functional

 Document title and edited state shown (if document-based)

Toolbars

 Toolbar present with common actions

 Toolbar is user-customizable

 Search field available in toolbar

Sidebars

 Sidebar for navigation (if app has multiple sections)

 Sidebar is collapsible

 Source list style with vibrancy

Keyboard

 Full keyboard navigation (Tab, arrows, Enter, Esc)

 Cmd+Z undo for all destructive actions

 Space for Quick Look previews

 Delete key removes selected items

 No keyboard traps (user can always Tab out)

Pointer

 Hover states on interactive elements

 Right-click context menus everywhere

 Drag and drop for content manipulation

 Cmd+Click for multi-selection

 Appropriate cursor changes

Notifications

 Notifications only for important events

 Alerts have suppression option for recurring ones

 No modal alerts for routine operations

System Integration

 High-quality Dock icon

 Content indexed in Spotlight (if applicable)

 Share menu works

 App Intents for Shortcuts

Visual Design

 System fonts at semantic sizes

 Dark Mode fully supported

 System accent color respected

 Translucency respects accessibility setting

 Consistent spacing on 8pt grid

Popovers

 Popover is anchored to its source element with an arrow pointing at it

 Pressing Esc dismisses the popover

 Popover is sized to its content without unnecessary scrolling

Accessibility

 All icon-only toolbar items and image buttons have accessibility labels

 Every action reachable by mouse is also reachable by keyboard (Full Keyboard Access)

 Decorative animations disabled when Reduce Motion is enabled

 Translucent surfaces replaced with solid backgrounds when Reduce Transparency is enabled

 VoiceOver traversal order is logical (top-left to bottom-right)

 Bold Text preference respected (SwiftUI handles automatically; AppKit checks accessibilityDisplayShouldUseBoldText)

 Increase Contrast preference respected (custom colors provide higher-contrast variants via colorSchemeContrast or accessibilityDisplayShouldIncreaseContrast)

Anti-Patterns

Do not do these things in a Mac app:

No menu bar — Every Mac app needs a menu bar. Period. A Mac app without menus is like a car without a steering wheel.

Hamburger menus — Never use a hamburger menu on Mac. The menu bar exists for this purpose. Hamburger menus signal a lazy iOS port.

Tab bars at the bottom — Mac apps use sidebars and toolbars, not iOS-style tab bars. If you need tabs, use actual document tabs in the tab bar (like Safari or Finder).

Large touch-sized targets — Mac controls should be compact (22-28pt height). Users have precise pointer input. Giant buttons waste space and look out of place.

Floating action buttons — FABs are a Material Design pattern. On Mac, place primary actions in the toolbar, menu bar, or as inline buttons.

Sheet for every action — Don't use modal sheets for simple operations. Use popovers, inline editing, or direct manipulation. Sheets should be reserved for multi-step workflows or important decisions.

Custom window chrome — Don't replace the standard title bar, traffic lights, or window controls with custom implementations. Users expect these to work consistently across all apps.

Ignoring keyboard — If a power user must reach for the mouse to perform common actions, your keyboard support is insufficient.

Single-window only — Unless your app is genuinely single-purpose (calculator, timer), support multiple windows. Users expect to Cmd+N for new windows.

Fixed window size — Non-resizable windows feel broken on Mac. Users have displays ranging from 13" laptops to 32" externals and expect to use that space.

No Cmd+Z undo — Every destructive or modifying action must be undoable. Users build muscle memory around Cmd+Z as their safety net.

Notification spam — Mac apps that send excessive notifications get their permissions revoked. Only notify for events that genuinely need attention.

Ignoring Dark Mode — A Mac app that looks wrong in Dark Mode appears abandoned. Always test both appearances.

Hardcoded colors — Use semantic system colors, not hardcoded hex values. Your colors should adapt to Light/Dark mode and accessibility settings automatically.

No drag and drop — Mac is a drag-and-drop platform. If users can see content, they expect to drag it somewhere.