animate

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

## MANDATORY PREPARATION

### Context Gathering (Do This First)

You cannot do a great job without having necessary context, such as target audience (critical), desired use-cases (critical), brand personality/tone (playful vs serious, energetic vs calm), and performance constraints.

Attempt to gather these from the current thread or codebase.

1. If you don't find *exact* information and have to infer from existing design and functionality, you MUST STOP and {{ask_instruction}} whether you got it right.
2. Otherwise, if you can't fully infer or your level of confidence is medium or lower, you MUST {{ask_instruction}} clarifying questions first to complete your context.

Do NOT proceed until you have answers. Guessing leads to inappropriate or excessive animation.

### Use frontend-design skill

Use the frontend-design skill for design principles and anti-patterns. Do NOT proceed until it has executed and you know all DO's and DON'Ts.

---

## 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_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
- **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):**
```css
/* 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
```css
/* Prefer for simple, declarative animations */
- transitions for state changes
- @keyframes for complex sequences
- transform + opacity only (GPU-accelerated)
```

### JavaScript Animation
```javascript
/* 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
```css
@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.