What problem does it solve? Building a Mac app that feels native requires knowing dozens of Apple Human Interface Guidelines rules covering menu bars, windows, toolbars, keyboard shortcuts, and accessibility. This Skill codifies 62 HIG rules with SwiftUI and AppKit code examples so developers and reviewers can apply them consistently when building or auditing macOS apps. ## Core Features & Use Cases - 62 Categorized Rules: Eleven sections covering Menu Bar, Windows, Toolbars, Sidebars, Keyboard, Pointer, Notifications, System Integration, Visual Design, Popovers, and Accessibility, each tagged CRITICAL, HIGH, or MEDIUM priority. - SwiftUI and AppKit Code Examples: Every rule includes working code for both frameworks, from CommandGroup menus to NSWindow configuration and VoiceOver labels. - Anti-Pattern Guardrails: Explicit "never do" list blocking iOS patterns like hamburger menus, bottom tab bars, and floating action buttons on Mac. - Use Case: When porting an iOS app to Mac via Catalyst, use this Skill to audit the UI against the checklist and fix violations like missing menu bar commands, non-resizable windows, or hardcoded colors that break Dark Mode. ## Quick Start Review my SwiftUI Mac app's main window code against the macOS design guidelines and list any violations of the CRITICAL rules.