hig

Apple HIG Design Intelligence

When to Use

• Building UI components with Apple-quality design (spring physics, semantic colors, 8pt grid)
• Reviewing existing code for HIG compliance
• Implementing animations with proper physics (not linear/ease-in-out)
• Analyzing reference videos to extract motion specs
• Generating design tokens for a project

Intent Router

Detect intent from the user's message and route to the appropriate mode:

Intent Keywords	Mode	What Happens
build, create, make, design, component	Build	Apply HIG rules while creating UI
review, check, scan, audit, compliance	Review	Run HIG scanner on source files
animate, motion, spring, gesture, transition	Animate	Implement animations with HIG physics
video + file path	Analyze	Extract motion spec from reference video
tokens, theme, design system	Tokens	Generate HIG design tokens
No clear intent	Interactive	Ask what the user wants

Build Mode

When building UI, load and apply these rules from design/hig/rules/:

1. Always: design-system.md (typography, colors, spacing, corners)
2. If animation involved: animation.md + craft.md (spring physics)
3. If navigation/modals: patterns.md (sheets, tabs, transitions)

Non-negotiable requirements:

• borderCurve: 'continuous' on all rounded elements
• Semantic color tokens, never hardcoded hex
• 4pt grid spacing, prefer 8pt
• 44pt minimum touch targets
• useReducedMotion with any animation
• expo-haptics on key interactions
• Dark mode support via useColorScheme
• Spring physics via withSpring, never withTiming with linear easing

Spring presets (use from design/hig/index.ts):

• smooth: default for most transitions
• snappy: button presses, toggles
• bouncy: playful elements, celebrations
• gentle: background, ambient motion

Review Mode

Run the HIG scanner from design/scanner/:

/erne-hig review ./src/screens/
/erne-hig review ./src/components/Button.tsx

Output: violations grouped by severity (critical → low), HIG score (0-100), grade (A-F), and fix suggestions.

Integrate with /erne-quality-gate — scanner runs automatically alongside code-reviewer and performance-profiler.

Animate Mode

Load craft.md + animation.md rules. Key patterns:

• Enter/Exit: FadeIn.duration(300).springify() — never abrupt appear/disappear
• Gesture-driven: Pan + withDecay for momentum, snap points with withSpring
• Scroll-linked: useAnimatedScrollHandler + interpolate with Extrapolation.CLAMP
• Choreography: parent first, children staggered 50ms, simultaneous for related

Analyze Mode

Process reference video through design/video/:

/erne-hig video ./reference.mp4

Auto-detects project stack, generates Reanimated/Gesture Handler code matching the video's motion patterns.

Tokens Mode

Generate typed design tokens from design/tokens/:

/erne-hig tokens

Creates theme/hig-tokens.ts with colors, typography, spacing, shadows — ready for useColorScheme and StyleSheet.create.