animate

name	animate
description	animate 动效：为功能添加有目的的 animation/transitions/micro-interactions/motion 效果。
argument-hint	[target]
user-invocable	true
context	fork
paths	*.tsx,*.jsx,*.vue,*.svelte,*.css,*.scss

Analyze a feature and strategically add animations and micro-interactions that enhance understanding, provide feedback, and create delight.

MANDATORY PREPARATION

Invoke /frontend-design — it contains design principles, anti-patterns, and the Context Gathering Protocol. Follow the protocol before proceeding — if no design context exists yet, you MUST run /teach-impeccable first. Additionally gather: performance constraints.

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Assess Animation Opportunities

Analyze where motion would improve the experience:

1. 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

2. 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 the user using AskUserQuestion.

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

• Page load choreography: Stagger element reveals (100-150ms delays), fade + slide combinations
• Hero section: Dramatic entrance for primary content (scale, parallax, or creative effects)
• Content reveals: Scroll-triggered animations using intersection observer
• Modal/drawer entry: Smooth slide + fade, backdrop fade, focus management

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

Durations by purpose:

• 100-150ms: Instant feedback (button press, toggle)
• 200-300ms: State changes (hover, menu open)
• 300-500ms: Layout changes (accordion, modal)
• 500-800ms: Entrance animations (page load)

Easing curves (use these, not CSS defaults):

/* Recommended - natural deceleration */
--ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);    /* Smooth, refined */
--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 + opacity only (GPU-accelerated)

JavaScript Animation

/* Use for complex, interactive animations */
- Web Animations API for programmatic control
- Framer Motion for React
- GSAP for complex sequences

Performance

• GPU acceleration: Use transform and opacity, avoid layout properties
• will-change: Add sparingly for known expensive animations
• Reduce paint: Minimize repaints, use contain where appropriate
• Monitor FPS: Ensure 60fps on target devices

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 (width, height, top, left)—use transform instead
• 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

Remember: Motion should enhance understanding and provide feedback, not just add decoration. Animate with purpose, respect performance constraints, and always consider accessibility. Great animation is invisible - it just makes everything feel right.