emilkowal-animations

name	emilkowal-animations
description	Emil Kowalski's animation best practices for web interfaces. Use when writing, reviewing, or implementing animations in React, CSS, or Framer Motion. Triggers on tasks involving transitions, easing, gestures, toasts, drawers, or motion.

Emil Kowalski Animation Best Practices

Comprehensive animation guide for web interfaces based on Emil Kowalski's teachings, open-source libraries (Sonner, Vaul), and his animations.dev course. Contains 43 rules across 7 categories, prioritized by impact.

When to Apply

Reference these guidelines when:

• Adding animations to React components
• Choosing easing curves or timing values
• Implementing gesture-based interactions (swipe, drag)
• Building toast notifications or drawer components
• Optimizing animation performance
• Ensuring animation accessibility

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Easing Selection	CRITICAL	ease-
2	Timing & Duration	CRITICAL	timing-
3	Property Selection	HIGH	props-
4	Transform Techniques	HIGH	transform-
5	Interaction Patterns	MEDIUM-HIGH	interact-
6	Strategic Animation	MEDIUM	strategy-
7	Accessibility & Polish	MEDIUM	polish-

Quick Reference

1. Easing Selection (CRITICAL)

• ease-out-default - Use ease-out as your default easing
• ease-custom-curves - Use custom cubic-bezier over built-in CSS
• ease-in-out-onscreen - Use ease-in-out for on-screen movement
• ease-spring-natural - Use spring animations for natural motion
• ease-ios-drawer - Use iOS-style easing for drawer components
• ease-context-matters - Match easing to animation context

2. Timing & Duration (CRITICAL)

• timing-300ms-max - Keep UI animations under 300ms
• timing-faster-better - Faster animations improve perceived performance
• timing-asymmetric - Use asymmetric timing for press and release
• timing-tooltip-delay - Delay initial tooltips, instant subsequent ones
• timing-drawer-500ms - Use 500ms duration for drawer animations

3. Property Selection (HIGH)

• props-transform-opacity - Animate only transform and opacity
• props-hardware-accelerated - Use hardware-accelerated animations when main thread is busy
• props-will-change - Use will-change to prevent 1px shift
• props-avoid-css-variables - Avoid CSS variables for drag animations
• props-clip-path-performant - Use clip-path for layout-free reveals

4. Transform Techniques (HIGH)

• transform-scale-097 - Scale buttons to 0.97 on press
• transform-never-scale-zero - Never animate from scale(0)
• transform-percentage-translate - Use percentage values for translateY
• transform-origin-aware - Make animations origin-aware
• transform-scale-children - Scale transforms affect children
• transform-3d-preserve - Use preserve-3d for 3D transform effects

5. Interaction Patterns (MEDIUM-HIGH)

• interact-interruptible - Make animations interruptible
• interact-momentum-dismiss - Use momentum-based dismissal
• interact-damping - Damp drag at boundaries
• interact-scroll-drag-conflict - Resolve scroll and drag conflicts
• interact-snap-points - Implement velocity-aware snap points
• interact-friction-upward - Allow upward drag with friction
• interact-pointer-capture - Use pointer capture for drag operations

6. Strategic Animation (MEDIUM)

• strategy-keyboard-no-animate - Never animate keyboard-initiated actions
• strategy-frequency-matters - Consider interaction frequency before animating
• strategy-purpose-required - Every animation must have a purpose
• strategy-feedback-immediate - Provide immediate feedback on all actions
• strategy-marketing-exception - Marketing sites are the exception

7. Accessibility & Polish (MEDIUM)

• polish-reduced-motion - Respect prefers-reduced-motion
• polish-opacity-fallback - Use opacity as reduced motion fallback
• polish-framer-hook - Use useReducedMotion hook in Framer Motion
• polish-dont-remove-all - Don't remove all animation for reduced motion
• polish-blur-bridge - Use blur to bridge animation states
• polish-clip-path-tabs - Use clip-path for tab transitions
• polish-toast-stacking - Implement toast stacking with scale and offset
• polish-scroll-reveal - Trigger scroll animations at appropriate threshold
• polish-hover-gap-fill - Fill gaps between hoverable elements
• polish-stagger-children - Stagger child animations for orchestration

Key Values Reference

Value	Usage
cubic-bezier(0.32, 0.72, 0, 1)	iOS-style drawer/sheet animation
scale(0.97)	Button press feedback
scale(0.95)	Minimum enter scale (never scale(0))
200ms ease-out	Standard UI transition
300ms	Maximum duration for UI animations
500ms	Drawer animation duration
0.11 px/ms	Velocity threshold for momentum dismiss
100px	Scroll-reveal viewport threshold
14px	Toast stack offset

Reference Files

Category	Example References
Easing	ease-context-matters, ease-ios-drawer
Timing	timing-300ms-max, timing-drawer-500ms
Props & Transform	props-transform-opacity, transform-scale-097
Interaction & Polish	interact-interruptible, polish-reduced-motion