* Add a platform axis (web / ios / android / adaptive) to the skill Orthogonal to register: register decides whether design IS or SERVES the product; platform decides the delivery target and which native conventions apply. Set `## Platform` in PRODUCT.md; a missing field defaults to `web`, so legacy projects are unaffected. - extractPlatform() in skill/scripts/context.mjs (mirrors extractRegister); the CLI appends a NEXT STEP directive to read the native reference(s). `adaptive` (Flutter / RN / KMP shipping both iOS and Android) loads both ios.md and android.md. - New reference/ios.md (Apple HIG distilled) and reference/android.md (Material 3 distilled); reference/web.md is a thin pointer. The native refs frame register's role as narrow: platform conformance is the bar, brand lives in the expressive layer the platform gives you, never by breaking the rails. - Setup step 5 loads the native reference(s) when platform is native. Live mode and the detect CLI stay web-only, gated off ios/android/adaptive. - init asks platform right after register; adapt/audit/animate/layout carry short platform divergence notes; all secondary spots thread `adaptive`. - a11y stays in audit.md (loading it at design time makes output timid), so the native refs carry no Accessibility section; audit.md's Platform section owns native a11y. - Tests: extractPlatform unit coverage + skill-behavior scenario 10 (PRODUCT.md platform ios -> agent loads ios.md). Source-first: only skill/, scripts/, tests/, CLAUDE.md, NOTICE.md, the changelog and version are committed; the sync workflow regenerates the provider trees and ./plugin on merge. ios.md / android.md are distilled from the MIT-licensed ehmo/platform-design-skills; attribution in NOTICE.md. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * Address review: gate web tools on native platforms, drop version churn Maintainer-review fixes applied with AI assistance (Claude Code), on top of the rebased platform-axis commit: - Design hook (post-edit and Cursor pre-edit) now resolves the project platform via loadContext + extractPlatform and skips its web rule scan for ios / android / adaptive projects, so React Native / Flutter code never draws web-shaped findings (new hook-lib resolveProjectPlatform / isNativePlatform helpers, covered by unit and subprocess tests). - context.mjs CLI warns on an unrecognized ## Platform value (e.g. a toolchain name like `flutter`) instead of silently defaulting to web; extractRegister / extractPlatform now share extractSectionValue. - Removed reference/web.md: nothing loaded it; CLAUDE.md carries the "web has no extra rulebook" explanation. - init.md: skip live-mode config (Step 6) for native platforms; note the per-app PRODUCT.md pattern for repos shipping web + native. - android.md: Material-everywhere apps that also ship on iPhone still owe iOS OS guarantees (safe areas, Reduce Motion, edge-swipe back). - ios.md: reworded a design-time line that framed Dynamic Type as an accessibility check (a11y stays owned by audit.md). - Renumbered the new skill-behavior scenario to 14 after main's 10-13; updated CLAUDE.md scenario list; added android + unrecognized-value CLI test cases. - No version or changelog changes: versioning happens at release time. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Tighten platform reference prose Editorial pass on the platform-axis text, applied with AI assistance (Claude Code) under maintainer direction: - ios.md / android.md rewritten to house style: single-line paragraphs (no hard wraps), one-sentence scope intro, deduplicated intro/slop-test, register-compression down to two sentences. In-file attribution paragraphs removed (NOTICE.md owns attribution); "read on top of the register reference" cruft removed (SKILL step 5 and the context.mjs directive already say it). Bans sections dropped: they restated the rules above them; the two additive items (tab-bar overload, hover-dependent affordances) folded into rules. ~40% smaller each. - Sub-command Platform sections (adapt, audit, animate, layout), SKILL step 5, init.md platform prose, and the context.mjs directive trimmed the same way. Build (prose validators, counts) and both test runners green. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Treat an empty PRODUCT.md section as absent, not the next heading Copilot review catch: extractSectionValue read the next `## ...` heading as the section value when a field was left empty, which made the CLI warn "value `## Product Purpose` is not recognized". Stop at the next heading and return null instead. Regression tests for extractPlatform, extractRegister, and the CLI warning path. Applied with AI assistance (Claude Code) under maintainer direction. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Only read a token list of both native targets as adaptive Bugbot catch: after the exact platform tokens failed, any Platform line containing the words ios and android was classified adaptive, so negated or explanatory prose ("web only, not ios or android") silently loaded both native refs and skipped the hook, with no warning. The combo parse now accepts only list separators and the two platform words; anything else falls through to the CLI's unrecognized-value WARNING. Regression tests added. Applied with AI assistance (Claude Code) under maintainer direction. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Co-authored-by: Paul Bakaus <paul.bakaus@gmail.com>
10 KiB
Additional context needed: performance constraints.
Add motion that conveys state, gives feedback, and clarifies hierarchy. Cut motion that exists only for decoration. Animation fatigue is a real cost; spend the budget on the moments that need it.
Register
Brand: motion is part of the voice; one well-rehearsed entrance beats scattered micro-interactions. The saturated AI default is fade-and-rise reveals on every scrolled section; that's a tell, not a choreography. Reserve scroll-triggered motion for moments that earn it.
Product: 150–250 ms on most transitions. Motion conveys state: feedback, reveal, loading, transitions between views. No page-load choreography; users are in a task and won't wait for it.
Platform
Native (ios / android / adaptive): motion mirrors the system. Match platform navigation transitions and honor the OS Reduce Motion setting; see the Motion sections of ios.md and android.md (adaptive follows each OS).
Assess Animation Opportunities
Analyze where motion would improve the experience:
-
Identify static areas:
- Missing feedback: Actions without visual acknowledgment (button clicks, form submission, etc.)
- Jarring transitions: Instant state changes that feel abrupt (show/hide, page loads, route changes)
- Unclear relationships: Spatial or hierarchical relationships that aren't obvious
- Lack of delight: Functional but joyless interactions
- Missed guidance: Opportunities to direct attention or explain behavior
-
Understand the context:
- What's the personality? (Playful vs serious, energetic vs calm)
- What's the performance budget? (Mobile-first? Complex page?)
- Who's the audience? (Motion-sensitive users? Power users who want speed?)
- What matters most? (One hero animation vs many micro-interactions?)
If any of these are unclear from the codebase, {{ask_instruction}}
CRITICAL: Respect prefers-reduced-motion. Always provide non-animated alternatives for users who need them.
Plan Animation Strategy
Create a purposeful animation plan:
- Hero moment: What's the ONE signature animation? (Page load? Hero section? Key interaction?)
- Feedback layer: Which interactions need acknowledgment?
- Transition layer: Which state changes need smoothing?
- Delight layer: Where can we surprise and delight?
IMPORTANT: One well-orchestrated experience beats scattered animations everywhere. Focus on high-impact moments.
Implement Animations
Add motion systematically across these categories:
Entrance Animations
-
Hero section: Dramatic entrance for primary content (scale, parallax, or creative effects)
-
Modal/drawer entry: Smooth slide + fade, backdrop fade, focus management
-
List rhythm: Sibling stagger is legitimate for cards-in-a-grid or list-items-appearing. Whole-section fade-on-scroll is not a list and is not legitimate. Cap total stagger time: 10 items at 50ms each = 500ms total. For more items, reduce per-item delay or cap the staggered count.
Use CSS custom properties for clean stagger:
animation-delay: calc(var(--i, 0) * 50ms)withstyle="--i: 0",style="--i: 1", etc. on each item.
Micro-interactions
- Button feedback:
- Hover: Subtle scale (1.02-1.05), color shift, shadow increase
- Click: Quick scale down then up (0.95 → 1), ripple effect
- Loading: Spinner or pulse state
- Form interactions:
- Input focus: Border color transition, slight scale or glow
- Validation: Shake on error, check mark on success, smooth color transitions
- Toggle switches: Smooth slide + color transition (200-300ms)
- Checkboxes/radio: Check mark animation, ripple effect
- Like/favorite: Scale + rotation, particle effects, color transition
State Transitions
- Show/hide: Fade + slide (not instant), appropriate timing (200-300ms)
- Expand/collapse: Height transition with overflow handling, icon rotation
- Loading states: Skeleton screen fades, spinner animations, progress bars
- Success/error: Color transitions, icon animations, gentle scale pulse
- Enable/disable: Opacity transitions, cursor changes
Navigation & Flow
- Page transitions: Crossfade between routes, shared element transitions
- Tab switching: Slide indicator, content fade/slide
- Carousel/slider: Smooth transforms, snap points, momentum
- Scroll effects: Parallax layers, sticky headers with state changes, scroll progress indicators
Feedback & Guidance
- Hover hints: Tooltip fade-ins, cursor changes, element highlights
- Drag & drop: Lift effect (shadow + scale), drop zone highlights, smooth repositioning
- Copy/paste: Brief highlight flash on paste, "copied" confirmation
- Focus flow: Highlight path through form or workflow
Delight Moments
- Empty states: Subtle floating animations on illustrations
- Completed actions: Confetti, check mark flourish, success celebrations
- Easter eggs: Hidden interactions for discovery
- Contextual animation: Weather effects, time-of-day themes, seasonal touches
Technical Implementation
Use appropriate techniques for each animation:
Timing & Easing
Duration: the 100/300/500 rule. Timing matters more than easing for "feels right":
| Duration | Use Case | Examples |
|---|---|---|
| 100–150ms | Instant feedback | Button press, toggle, color change |
| 200–300ms | State changes | Menu open, tooltip, hover state |
| 300–500ms | Layout changes | Accordion, modal, drawer |
| 500–800ms | Entrance animations | Page load, hero reveal |
Easing curves (use these, not CSS defaults):
/* Recommended: natural deceleration */
--ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1); /* Smooth */
--ease-out-quint: cubic-bezier(0.22, 1, 0.36, 1); /* Slightly snappier */
--ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1); /* Confident, decisive */
/* AVOID: feel dated and tacky */
/* bounce: cubic-bezier(0.34, 1.56, 0.64, 1); */
/* elastic: cubic-bezier(0.68, -0.6, 0.32, 1.6); */
Exit animations are faster than entrances. Use ~75% of enter duration.
CSS Animations
/* Prefer for simple, declarative animations */
- transitions for state changes
- @keyframes for complex sequences
- transform and opacity for reliable movement
- blur, filters, masks, clip paths, shadows, and color shifts for premium atmospheric effects when verified smooth
JavaScript Animation
/* Use for complex, interactive animations */
- Web Animations API for programmatic control
- Framer Motion for React
- GSAP for complex sequences
Motion Materials
Transform and opacity are reliable defaults, not the whole palette. Premium interfaces often need atmospheric properties. Match material to effect:
- Transform / opacity: movement, press feedback, simple reveals, list choreography
- Blur / filter / backdrop-filter: focus pulls, depth, glass or lens effects, softened entrances
- Clip-path / masks: wipes, reveals, editorial cropping, product-like transitions
- Shadow / glow / color filters: energy, affordance, focus, warmth, active state
- Grid-template-rows or FLIP-style transforms: expanding and reflowing layout without animating
heightdirectly
The hard rule isn't "transform and opacity only." It's: avoid animating layout-driving properties casually (width, height, top, left, margins), keep expensive effects bounded to small or isolated areas, and verify smoothness in-browser on target viewports.
Performance
- Layout safety: Avoid casual animation of layout-driving properties (
width,height,top,left, margins) - will-change: Add sparingly for known expensive animations only (e.g. on
:hoveror an.animatingclass), never preemptively across the whole page - Scroll triggers: Use Intersection Observer instead of scroll event listeners; unobserve after the animation fires once
- Bound expensive effects: Keep blur/filter/shadow areas small or isolated, use
containwhere appropriate - Monitor FPS: Ensure 60fps on target devices
Perceived Performance
Nobody cares how fast your site is, only how fast it feels. The 80ms threshold: anything under ~80ms feels instant because our brains buffer sensory input for that long to synchronize perception. Target this for micro-interactions.
- Preemptive start: Begin transitions immediately while loading (iOS app zoom, skeleton UI). Users perceive work happening.
- Early completion: Show content progressively, don't wait for everything (progressive images, streaming HTML, skeleton fade-ins).
- Optimistic UI: Update the interface immediately, handle failures gracefully. Use for low-stakes actions (likes, follows). Avoid for payments or destructive operations.
- Easing affects perceived duration: Ease-in (accelerating toward completion) makes tasks feel shorter because the peak-end effect weights final moments heavily. Ease-out feels satisfying for entrances.
- Caution: Too-fast responses can decrease perceived value for complex operations (search, analysis). Sometimes a brief delay signals "real work" is happening.
Accessibility
@media (prefers-reduced-motion: reduce) {
* {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}
NEVER:
- Use bounce or elastic easing curves; they feel dated and draw attention to the animation itself
- Animate layout properties casually (
width,height,top,left, margins) when transform, FLIP, or grid-based techniques would work - Use durations over 500ms for feedback (it feels laggy)
- Animate without purpose (every animation needs a reason)
- Ignore
prefers-reduced-motion(this is an accessibility violation) - Animate everything (animation fatigue makes interfaces feel exhausting)
- Block interaction during animations unless intentional
Verify Quality
Test animations thoroughly:
- Smooth at 60fps: No jank on target devices
- Feels natural: Easing curves feel organic, not robotic
- Appropriate timing: Not too fast (jarring) or too slow (laggy)
- Reduced motion works: Animations disabled or simplified appropriately
- Doesn't block: Users can interact during/after animations
- Adds value: Makes interface clearer or more delightful
When the motion clarifies state instead of decorating it, hand off to {{command_prefix}}impeccable polish for the final pass.