Design & HIG

You MUST use this skill for ANY visual design, HIG compliance, Liquid Glass, SF Symbols, typography, or app composition work.

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Not on Claude Code? Where this router says "Launch some-auditor agent", read that auditor's file in this suite and follow it inline — the same procedure, needing only file search and read.

Available here: skills/liquid-glass-auditor.md.

Agents that need Bash — builds, tests, simulators, crash symbolication — stay Claude Code-only; there is no inline equivalent for those.

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Quick Reference

Symptom / Task	Reference
Design decisions, HIG compliance, colors, backgrounds	See skills/hig.md
Semantic colors, custom color patterns, material styles	See skills/hig-ref.md
Liquid Glass effects, adoption, migration from blur effects	See skills/liquid-glass.md
App-wide Liquid Glass adoption, backward compatibility	See skills/liquid-glass-ref.md
SF Symbols rendering modes, effects, animations	See skills/sf-symbols.md
SF Symbols API signatures, UIKit equivalents, availability	See skills/sf-symbols-ref.md
San Francisco fonts, text styles, Dynamic Type, tracking	See skills/typography-ref.md
App entry points, auth flows, root view switching, scene lifecycle, document-based apps	See skills/app-composition.md
Apple Pay button / Wallet pass design / Tap to Pay button	See axiom-payments suite, plus skills/hig.md for cross-cutting HIG context

Decision Tree

digraph design {
    start [label="Design task" shape=ellipse];
    what [label="What do you need?" shape=diamond];

    start -> what;
    what -> "skills/hig.md" [label="design decision,\nHIG compliance,\ncolor/background choice"];
    what -> "skills/hig-ref.md" [label="semantic color API,\ncustom color code,\nmaterial style details"];
    what -> "skills/liquid-glass.md" [label="Liquid Glass effects,\nmigrate from blur,\nRegular vs Clear"];
    what -> "skills/liquid-glass-ref.md" [label="app-wide Liquid Glass plan,\nplatform differences,\nbackward compat"];
    what -> "skills/sf-symbols.md" [label="rendering mode choice,\nsymbol effects/animations,\ncustom symbols"];
    what -> "skills/sf-symbols-ref.md" [label="SF Symbols API syntax,\nUIKit equivalents,\navailability matrix"];
    what -> "skills/typography-ref.md" [label="font selection,\nDynamic Type,\ntext styles, tracking"];
    what -> "skills/app-composition.md" [label="@main entry point,\nauth flow, root view,\nscene lifecycle"];
}

1. Design decision / HIG compliance / choosing colors or backgrounds? → skills/hig.md 1a. Need semantic color API, custom color code, or material style details? → skills/hig-ref.md
2. Liquid Glass effects / migrating from blur / Regular vs Clear variant? → skills/liquid-glass.md 2a. Planning app-wide Liquid Glass adoption / platform differences / backward compatibility? → skills/liquid-glass-ref.md
3. SF Symbols rendering mode / symbol effects / custom symbols? → skills/sf-symbols.md 3a. Need SF Symbols API syntax / UIKit equivalents / availability check? → skills/sf-symbols-ref.md
4. Font selection / Dynamic Type / text styles / tracking / leading? → skills/typography-ref.md
5. App entry point / auth flow / root view switching / scene lifecycle? → skills/app-composition.md
6. SwiftUI view implementation? → /skill axiom-swiftui
7. TextKit / rich text editing / Writing Tools? → /skill axiom-uikit
8. Accessibility compliance (VoiceOver, contrast, touch targets)? → /skill axiom-accessibility
9. Audit UI for Liquid Glass adoption? → liquid-glass-auditor (Agent — surfaces migration opportunities AND adoption-completeness gaps: variant discipline, nesting hygiene, availability gating, primary-action tinting, accessibility re-check; scores ADOPTED / PARTIAL / NOT ADOPTED)
10. CarPlay app design, categories, driver-distraction rules? → /skill axiom-media (carplay-hig.md)

Platform-specific HIG

• watchOS design (glanceable UI, watchOS 10 navigation) → See axiom-watchos (skills/design-for-watchos.md)

Conflict Resolution

design vs swiftui: When building UI:

1. Use design FIRST — Decide what to build (colors, materials, typography, layout intent) before how to build it.
2. Then use swiftui — Implement the design decision in SwiftUI code.

design vs accessibility: When choosing colors or typography:

• Color contrast or Dynamic Type compliance? → use accessibility
• Which semantic color or text style to pick? → use design

design (liquid-glass) vs swiftui: When implementing Liquid Glass:

• What Liquid Glass is, when to use Regular vs Clear, migration strategy → use design (skills/liquid-glass.md)
• SwiftUI code for .glassEffect() modifier → use design (skills/liquid-glass-ref.md), then swiftui for surrounding view code

design (app-composition) vs swiftui: When structuring app architecture:

• @main entry, auth state machine, root view switching, scene lifecycle → use design (skills/app-composition.md)
• NavigationStack, NavigationSplitView, tab structure → use swiftui

design vs media (CarPlay): When designing for CarPlay:

• General iOS HIG principles (colors, typography, Liquid Glass) → use design
• CarPlay-specific rules (app categories, entitlement review, template-only UI, driver distraction, per-category design rules) → invoke axiom-media (skills/carplay-hig.md)
• CarPlay rules are stricter than iOS HIG and enforced at entitlement review, not just App Store review.

Critical Patterns

HIG Quick Decisions (skills/hig.md):

• Background color decision tree (media-focused vs standard)
• Typography selection (headline vs body vs caption)
• Color usage guidelines and when to use semantic vs custom colors
• Design review checklist for HIG compliance

HIG Comprehensive Reference (skills/hig-ref.md):

• All semantic colors with platform availability
• Custom color patterns with dark mode support
• Background hierarchy and material styles
• Code examples for every color and background pattern

Liquid Glass (skills/liquid-glass.md):

• What Liquid Glass is and how it differs from blur effects
• Regular vs Clear variant selection
• Migration strategy from pre-iOS 26 materials
• Tinting, legibility, and adaptive behavior troubleshooting
• Expert review criteria for Liquid Glass implementations

Liquid Glass Adoption (skills/liquid-glass-ref.md):

• App-wide adoption planning (icons, controls, navigation, menus)
• Platform-specific behavior (iOS, iPadOS, macOS, tvOS, watchOS)
• Backward compatibility strategy for supporting pre-Liquid Glass
• Accessibility compliance with Liquid Glass interfaces

SF Symbols (skills/sf-symbols.md):

• Rendering mode selection (Monochrome, Hierarchical, Palette, Multicolor)
• Symbol effect selection (Bounce, Pulse, Scale, Wiggle, Rotate, Breathe, Draw)
• Custom symbol creation workflow
• Troubleshooting effects not playing, weight mismatches

SF Symbols API (skills/sf-symbols-ref.md):

• Exact API signatures for rendering modes and effects
• UIKit/AppKit equivalents for every SwiftUI symbol API
• Platform availability matrix
• Configuration options (weight, scale, variable values)

Typography (skills/typography-ref.md):

• San Francisco font system (Pro, Compact, Mono, New York)
• Text styles with Dynamic Type scaling
• Tracking and leading values
• Internationalization considerations

App Composition (skills/app-composition.md):

• @main entry point and root view patterns
• Authentication state machine (login, onboarding, main)
• Flicker-free root view switching
• scenePhase lifecycle handling and state restoration
• Document-based apps: the OS27 @Observable document model (ReadableDocument/WritableDocument) + DocumentGroup

Anti-Rationalization

Thought	Reality
"I'll just pick colors that look good"	Semantic colors adapt to dark mode, accessibility settings, and platform automatically. Custom colors need all of that manually. skills/hig.md has the decision tree.
"Liquid Glass is just a blur effect"	Liquid Glass is a distinct material system with lensing, tinting, and adaptive behavior. Using .blur() instead creates a visually wrong result. skills/liquid-glass.md explains the difference.
"I know which SF Symbol rendering mode to use"	The right mode depends on context (monochrome for toolbars, hierarchical for depth, palette for brand colors). skills/sf-symbols.md has the decision tree.
"I'll hardcode font sizes"	Hardcoded sizes break Dynamic Type, violate HIG, and fail accessibility review. skills/typography-ref.md shows the text style system.
"I'll handle auth state with a boolean"	A boolean can't represent login, onboarding, and main states without race conditions. skills/app-composition.md has the state machine pattern.
"Liquid Glass adoption means rewriting my whole UI"	Most standard SwiftUI/UIKit components adopt automatically. Start by building with latest Xcode, then review. skills/liquid-glass-ref.md has the incremental strategy.
"I'll add the SF Symbol animation later"	Symbol effects are the primary way users perceive interactive feedback. Shipping without them feels broken. skills/sf-symbols.md covers selection.
"I'll skip the design review, the code works"	HIG compliance affects App Store review. Reviewers reject apps that feel wrong even if they function correctly. skills/hig.md has the review checklist.

Example Invocations

User: "Should I use a dark or light background?" -> Read: skills/hig.md

User: "What semantic color should I use for secondary text?" -> Read: skills/hig-ref.md

User: "How do I implement Liquid Glass in my app?" -> Read: skills/liquid-glass.md

User: "I need to plan Liquid Glass adoption across my whole app" -> Read: skills/liquid-glass-ref.md

User: "My SF Symbol is flat, I want it to have depth" -> Read: skills/sf-symbols.md

User: "What's the SwiftUI API for symbol effects?" -> Read: skills/sf-symbols-ref.md

User: "Which font should I use for body text?" -> Read: skills/typography-ref.md

User: "How do I switch between login and main screens?" -> Read: skills/app-composition.md

User: "Check my app's UI for HIG compliance" -> Read: skills/hig.md, then /skill axiom-accessibility for contrast/Dynamic Type

User: "I want my download button icon to animate" -> Read: skills/sf-symbols.md