Microinteractions and Motion Design

Animated feedback, delightful transitions, and purposeful motion that make interfaces feel alive, responsive, and intuitive.

Core Principles

1. Feedback Over Decoration

Every animation should communicate something: confirmation, progress, state change. Motion without purpose is noise.

2. Natural and Physical

Animations should obey a sense of physics. Elements accelerate into motion and decelerate to a stop, not teleport.

3. Fast by Default

Most UI animations should complete in 150-400ms. Users notice delays above 400ms and get frustrated above 1000ms.

4. Consistent Timing Language

Use the same easing curves and durations across your product. A button hover should feel like it belongs with a modal open.

5. Respect User Preferences

Always provide a reduced-motion fallback. Some users experience motion sickness or have vestibular disorders.

Animation Timing Reference

Easing Functions

:root {
  /* Standard easings */
  --ease-out: cubic-bezier(0.0, 0.0, 0.2, 1);       /* Decelerate - entering elements */
  --ease-in: cubic-bezier(0.4, 0.0, 1, 1);           /* Accelerate - exiting elements */
  --ease-in-out: cubic-bezier(0.4, 0.0, 0.2, 1);     /* Standard - moving elements */

  /* Expressive easings */
  --ease-bounce: cubic-bezier(0.34, 1.56, 0.64, 1);  /* Overshoot and settle */
  --ease-snap: cubic-bezier(0.5, 0, 0.1, 1);         /* Quick snap into place */
  --ease-smooth: cubic-bezier(0.25, 0.1, 0.25, 1);   /* Gentle, smooth motion */

  /* Spring-like */
  --ease-spring: cubic-bezier(0.175, 0.885, 0.32, 1.275);

  /* Standard durations */
  --duration-fast: 150ms;
  --duration-normal: 250ms;
  --duration-slow: 400ms;
  --duration-slower: 600ms;
}

Hover States

Button Hover Effects

/* Basic lift effect */
.btn-lift {
  padding: 12px 28px;
  background: #6c5ce7;
  color: #ffffff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out);
}

.btn-lift:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(108, 92, 231, 0.4);
}

.btn-lift:active {
  transform: translateY(0);
  box-shadow: 0 1px 4px rgba(108, 92, 231, 0.3);
}

/* Fill sweep effect */
.btn-sweep {
  position: relative;
  padding: 12px 28px;
  background: transparent;
  color: #6c5ce7;
  border: 2px solid #6c5ce7;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  overflow: hidden;
  z-index: 1;
  transition: color var(--duration-normal) var(--ease-out);
}

.btn-sweep::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: #6c5ce7;
  z-index: -1;
  transition: left var(--duration-normal) var(--ease-out);
}

.btn-sweep:hover {
  color: #ffffff;
}

.btn-sweep:hover::before {
  left: 0;
}

/* Pulse glow effect */
.btn-glow {
  padding: 12px 28px;
  background: #6c5ce7;
  color: #ffffff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: box-shadow var(--duration-normal) var(--ease-out);
}

.btn-glow:hover {
  box-shadow: 0 0 0 4px rgba(108, 92, 231, 0.3);
}

.btn-glow:focus-visible {
  outline: none;
  box-shadow: 0 0 0 4px rgba(108, 92, 231, 0.5);
}

Card Hover Effects

/* Subtle lift with shadow growth */
.card-hover {
  padding: 32px;
  background: #ffffff;
  border-radius: 12px;
  border: 1px solid #e2e8f0;
  transition: transform var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out),
              border-color var(--duration-normal) var(--ease-out);
}

.card-hover:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
  border-color: transparent;
}

/* Image zoom within card */
.card-image-zoom {
  overflow: hidden;
  border-radius: 12px 12px 0 0;
}

.card-image-zoom img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--duration-slow) var(--ease-out);
}

.card-hover:hover .card-image-zoom img {
  transform: scale(1.05);
}

Link Hover Effects

/* Underline grow from center */
.link-grow {
  color: #2d3436;
  text-decoration: none;
  position: relative;
}

.link-grow::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  width: 0;
  height: 2px;
  background: #6c5ce7;
  transition: width var(--duration-normal) var(--ease-out),
              left var(--duration-normal) var(--ease-out);
}

.link-grow:hover::after {
  width: 100%;
  left: 0;
}

/* Underline slide from left */
.link-slide {
  color: #2d3436;
  text-decoration: none;
  position: relative;
}

.link-slide::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: #6c5ce7;
  transition: width var(--duration-normal) var(--ease-out);
}

.link-slide:hover::after {
  width: 100%;
}

/* Background highlight */
.link-highlight {
  color: #2d3436;
  text-decoration: none;
  padding: 2px 4px;
  margin: -2px -4px;
  border-radius: 4px;
  transition: background var(--duration-fast) var(--ease-out),
              color var(--duration-fast) var(--ease-out);
}

.link-highlight:hover {
  background: #6c5ce7;
  color: #ffffff;
}

Loading Animations

Skeleton Screens

<div class="skeleton-card">
  <div class="skeleton skeleton--image"></div>
  <div class="skeleton skeleton--title"></div>
  <div class="skeleton skeleton--text"></div>
  <div class="skeleton skeleton--text skeleton--short"></div>
</div>

.skeleton {
  background: #e2e8f0;
  border-radius: 4px;
  position: relative;
  overflow: hidden;
}

/* Shimmer animation */
.skeleton::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.4),
    transparent
  );
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
  100% {
    left: 100%;
  }
}

.skeleton--image {
  width: 100%;
  height: 200px;
  border-radius: 8px;
  margin-bottom: 16px;
}

.skeleton--title {
  width: 60%;
  height: 24px;
  margin-bottom: 12px;
}

.skeleton--text {
  width: 100%;
  height: 16px;
  margin-bottom: 8px;
}

.skeleton--short {
  width: 40%;
}

Spinner Variations

/* Simple ring spinner */
.spinner-ring {
  width: 40px;
  height: 40px;
  border: 3px solid #e2e8f0;
  border-top-color: #6c5ce7;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Dot pulse */
.spinner-dots {
  display: flex;
  gap: 8px;
}

.spinner-dots__dot {
  width: 10px;
  height: 10px;
  background: #6c5ce7;
  border-radius: 50%;
  animation: pulse 1.4s ease-in-out infinite;
}

.spinner-dots__dot:nth-child(2) { animation-delay: 0.2s; }
.spinner-dots__dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes pulse {
  0%, 80%, 100% {
    transform: scale(0.6);
    opacity: 0.4;
  }
  40% {
    transform: scale(1);
    opacity: 1;
  }
}

/* Progress bar */
.progress-bar {
  width: 100%;
  height: 4px;
  background: #e2e8f0;
  border-radius: 2px;
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  background: #6c5ce7;
  border-radius: 2px;
  transition: width var(--duration-slow) var(--ease-out);
}

/* Indeterminate progress */
.progress-bar--indeterminate .progress-bar__fill {
  width: 30%;
  animation: indeterminate 1.5s ease-in-out infinite;
}

@keyframes indeterminate {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(400%); }
}

Transitions

Modal Open/Close

<div class="modal-overlay" id="modal">
  <div class="modal-content">
    <h2>Modal Title</h2>
    <p>Modal content goes here.</p>
    <button onclick="closeModal()">Close</button>
  </div>
</div>

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  display: grid;
  place-items: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--duration-normal) var(--ease-out),
              visibility var(--duration-normal);
  z-index: 1000;
}

.modal-overlay.is-open {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: #ffffff;
  border-radius: 16px;
  padding: 40px;
  max-width: 500px;
  width: 90%;
  transform: translateY(20px) scale(0.95);
  transition: transform var(--duration-normal) var(--ease-out);
}

.modal-overlay.is-open .modal-content {
  transform: translateY(0) scale(1);
}

Accordion / Collapsible

<div class="accordion">
  <button class="accordion__trigger" aria-expanded="false">
    <span>Section Title</span>
    <svg class="accordion__icon" viewBox="0 0 24 24" width="20" height="20">
      <polyline points="6 9 12 15 18 9" fill="none" stroke="currentColor" stroke-width="2"/>
    </svg>
  </button>
  <div class="accordion__panel">
    <div class="accordion__content">
      <p>Collapsible content goes here.</p>
    </div>
  </div>
</div>

.accordion__trigger {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  padding: 16px 20px;
  background: none;
  border: none;
  border-bottom: 1px solid #e2e8f0;
  font-size: 1rem;
  font-weight: 600;
  color: #2d3436;
  cursor: pointer;
  transition: background var(--duration-fast) var(--ease-out);
}

.accordion__trigger:hover {
  background: #f8f9fa;
}

.accordion__icon {
  transition: transform var(--duration-normal) var(--ease-out);
}

.accordion__trigger[aria-expanded="true"] .accordion__icon {
  transform: rotate(180deg);
}

.accordion__panel {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--duration-normal) var(--ease-out);
}

.accordion__trigger[aria-expanded="true"] + .accordion__panel {
  grid-template-rows: 1fr;
}

.accordion__content {
  overflow: hidden;
}

Tab Switching

/* Animated tab indicator */
.tabs {
  position: relative;
  display: flex;
  gap: 0;
  border-bottom: 2px solid #e2e8f0;
}

.tab {
  padding: 12px 24px;
  background: none;
  border: none;
  font-size: 1rem;
  font-weight: 500;
  color: #636e72;
  cursor: pointer;
  transition: color var(--duration-fast) var(--ease-out);
}

.tab.is-active {
  color: #6c5ce7;
}

/* Sliding indicator bar */
.tabs__indicator {
  position: absolute;
  bottom: -2px;
  height: 2px;
  background: #6c5ce7;
  transition: left var(--duration-normal) var(--ease-out),
              width var(--duration-normal) var(--ease-out);
}

/* Tab content crossfade */
.tab-panel {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity var(--duration-normal) var(--ease-out),
              transform var(--duration-normal) var(--ease-out);
  display: none;
}

.tab-panel.is-active {
  display: block;
  opacity: 1;
  transform: translateY(0);
}

Scroll Animations

Reveal on Scroll (CSS Only)

/* Use CSS animation-timeline for scroll-driven animations */
.scroll-reveal {
  opacity: 0;
  transform: translateY(30px);
  animation: reveal linear forwards;
  animation-timeline: view();
  animation-range: entry 0% entry 30%;
}

@keyframes reveal {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

Scroll Reveal With Intersection Observer

<div class="reveal" data-reveal>
  <h2>This appears on scroll</h2>
</div>

.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.reveal.is-visible > *:nth-child(1) { transition-delay: 0ms; }
.reveal.is-visible > *:nth-child(2) { transition-delay: 100ms; }
.reveal.is-visible > *:nth-child(3) { transition-delay: 200ms; }
.reveal.is-visible > *:nth-child(4) { transition-delay: 300ms; }

/* Intersection Observer for scroll reveals */
const observer = new IntersectionObserver(
  (entries) => {
    entries.forEach(entry => {
      if (entry.isIntersecting) {
        entry.target.classList.add('is-visible');
        observer.unobserve(entry.target); /* animate once */
      }
    });
  },
  { threshold: 0.15, rootMargin: '0px 0px -50px 0px' }
);

document.querySelectorAll('[data-reveal]').forEach(el => {
  observer.observe(el);
});

Parallax Scrolling

/* Pure CSS parallax with perspective */
.parallax-container {
  height: 100vh;
  overflow-x: hidden;
  overflow-y: auto;
  perspective: 1px;
}

.parallax-layer--back {
  transform: translateZ(-1px) scale(2);
  position: absolute;
  inset: 0;
  z-index: -1;
}

.parallax-layer--front {
  transform: translateZ(0);
  position: relative;
  z-index: 1;
}

Scroll-Linked Progress Bar

/* Page scroll progress indicator */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
  z-index: 9999;
}

.scroll-progress__bar {
  height: 100%;
  background: #6c5ce7;
  width: 0%;
  animation: scroll-progress linear forwards;
  animation-timeline: scroll(root);
}

@keyframes scroll-progress {
  to { width: 100%; }
}

CSS Animation Techniques

Staggered Grid Animation

.stagger-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px;
}

.stagger-grid__item {
  opacity: 0;
  transform: translateY(20px);
  animation: stagger-in var(--duration-slow) var(--ease-out) forwards;
}

/* Calculate delay based on position */
.stagger-grid__item:nth-child(1) { animation-delay: 0ms; }
.stagger-grid__item:nth-child(2) { animation-delay: 80ms; }
.stagger-grid__item:nth-child(3) { animation-delay: 160ms; }
.stagger-grid__item:nth-child(4) { animation-delay: 240ms; }
.stagger-grid__item:nth-child(5) { animation-delay: 320ms; }
.stagger-grid__item:nth-child(6) { animation-delay: 400ms; }

@keyframes stagger-in {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

Notification Toast

<div class="toast is-visible">
  <span class="toast__icon">&#10003;</span>
  <span class="toast__message">Changes saved successfully</span>
</div>

.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 20px;
  background: #2d3436;
  color: #ffffff;
  border-radius: 8px;
  font-size: 0.9375rem;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
  transform: translateY(100px);
  opacity: 0;
  transition: transform var(--duration-normal) var(--ease-spring),
              opacity var(--duration-normal) var(--ease-out);
  z-index: 9999;
}

.toast.is-visible {
  transform: translateY(0);
  opacity: 1;
}

.toast__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: #00b894;
  border-radius: 50%;
  font-size: 0.75rem;
  flex-shrink: 0;
}

Toggle Switch

<label class="toggle">
  <input type="checkbox" class="toggle__input" />
  <span class="toggle__track">
    <span class="toggle__thumb"></span>
  </span>
</label>

.toggle__input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle__track {
  display: inline-flex;
  align-items: center;
  width: 48px;
  height: 28px;
  background: #cbd5e0;
  border-radius: 14px;
  padding: 2px;
  cursor: pointer;
  transition: background var(--duration-normal) var(--ease-out);
}

.toggle__thumb {
  width: 24px;
  height: 24px;
  background: #ffffff;
  border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
  transition: transform var(--duration-normal) var(--ease-spring);
}

.toggle__input:checked + .toggle__track {
  background: #6c5ce7;
}

.toggle__input:checked + .toggle__track .toggle__thumb {
  transform: translateX(20px);
}

.toggle__input:focus-visible + .toggle__track {
  box-shadow: 0 0 0 3px rgba(108, 92, 231, 0.4);
}

Ripple Effect

/* Material-style ripple on click */
.ripple {
  position: relative;
  overflow: hidden;
}

.ripple::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  transition: width 0.5s ease, height 0.5s ease, opacity 0.5s ease;
  opacity: 0;
}

.ripple:active::after {
  width: 300px;
  height: 300px;
  opacity: 1;
  transition: 0s;
}

Page Transitions

Crossfade Between Pages

/* View Transitions API (modern browsers) */
@view-transition {
  navigation: auto;
}

/* Default crossfade */
::view-transition-old(root) {
  animation: fade-out 250ms ease-out;
}

::view-transition-new(root) {
  animation: fade-in 250ms ease-in;
}

@keyframes fade-out {
  from { opacity: 1; }
  to { opacity: 0; }
}

@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Slide transition for specific elements */
.hero-image {
  view-transition-name: hero;
}

::view-transition-old(hero) {
  animation: slide-out-left 300ms ease-out;
}

::view-transition-new(hero) {
  animation: slide-in-right 300ms ease-out;
}

@keyframes slide-out-left {
  to { transform: translateX(-100%); opacity: 0; }
}

@keyframes slide-in-right {
  from { transform: translateX(100%); opacity: 0; }
}

Performance Considerations

What to Animate

Performance Best Practices

/* GOOD: animate only transform and opacity (composited) */
.performant {
  transition: transform 250ms ease-out, opacity 250ms ease-out;
}

.performant:hover {
  transform: translateY(-4px) scale(1.02);
  opacity: 0.9;
}

/* BAD: animating layout properties causes reflow */
.slow {
  transition: width 250ms, height 250ms, margin 250ms;
}

/* Promote to GPU layer for complex animations */
.gpu-layer {
  will-change: transform;
  /* Remove will-change after animation completes */
}

/* Use contain for isolated animations */
.animated-card {
  contain: layout style paint;
}

Animating Box Shadows Efficiently

/* BAD: directly animating box-shadow is expensive */
.card-bad:hover {
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* GOOD: animate a pseudo-element's opacity instead */
.card-good {
  position: relative;
}

.card-good::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-out);
  z-index: -1;
}

.card-good:hover::after {
  opacity: 1;
}

Reduced Motion

/* CRITICAL: always respect user preferences */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Or selectively remove non-essential animations */
@media (prefers-reduced-motion: reduce) {
  .scroll-reveal {
    opacity: 1;
    transform: none;
    animation: none;
  }

  .parallax-layer--back {
    transform: none;
  }

  /* Keep functional animations (loading spinners, progress) */
  .spinner-ring {
    animation-duration: 1.5s; /* slow down but keep */
  }
}

When to Use Microinteractions

Perfect For

• SaaS products: Feedback on saves, deletes, status changes
• E-commerce: Add-to-cart, wishlist, checkout progress
• Forms: Validation feedback, step transitions
• Dashboards: Data loading, chart reveals, filter transitions
• Mobile apps: Touch feedback, pull-to-refresh, swipe actions
• Portfolios: Project reveals, image galleries, page transitions

Real-World Examples

• Stripe - Smooth page transitions, animated gradients
• Linear - Silky keyboard shortcuts, list animations
• Vercel - Deployment progress, subtle hover states
• Notion - Block drag-and-drop, inline transitions
• Apple - Scroll-driven product reveals
• GitHub - Contribution graph, PR merge animations

Avoid For

• Content-heavy sites: Don't slow down reading with animation
• Accessibility-critical: Government, healthcare (keep functional only)
• Slow connections: Heavy animation punishes low-bandwidth users
• Data entry forms: Speed matters more than delight

Pros and Cons

Advantages

• Makes interfaces feel responsive and alive
• Provides clear feedback on user actions
• Guides attention to important changes
• Creates emotional connection and delight
• Can explain spatial relationships (where things come from/go to)
• Differentiates from static competitors

Disadvantages

• Easy to overdo; too much motion is distracting and nauseating
• Performance impact if using wrong properties
• Increases development and testing time
• Can annoy power users who want speed
• Must maintain reduced-motion alternatives
• Inconsistent animation is worse than no animation

Common Mistakes

1. Animating Everything

Wrong: Every element bounces, slides, and fades on every page load.
Right: Animate meaningfully. State changes, user actions, and attention guidance.

2. Using Wrong Properties

Wrong: Animating width, height, top, left, margin.

/* Wrong - triggers layout recalculation every frame */
.card:hover {
  width: 320px;
  margin-top: -10px;
}

Right: Use transform and opacity exclusively for motion.

/* Right - GPU-composited, smooth 60fps */
.card:hover {
  transform: scale(1.05) translateY(-10px);
}

3. Ignoring Reduced Motion

Wrong: No prefers-reduced-motion media query.
Right: Always provide a reduced-motion fallback (see Performance section).

4. Inconsistent Timing

Wrong: Button hovers at 100ms, cards at 500ms, modals at 200ms, no cohesion.
Right: Define a timing system with CSS custom properties and use it everywhere.

5. Blocking User Input

Wrong: Long entrance animations that prevent interaction.

/* Wrong - user can't click for 1.5 seconds */
.hero { animation: elaborate-entrance 1.5s ease; }

Right: Keep entrance animations under 500ms, or make elements interactive immediately.

Advanced Techniques

Shared Element Transitions

/* Assign view-transition-name to elements that persist across pages */
.product-card__image {
  view-transition-name: product-image;
}

.product-detail__image {
  view-transition-name: product-image;
}

/* The browser automatically morphs between the two positions */
::view-transition-group(product-image) {
  animation-duration: 350ms;
  animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
}

Number Counter Animation

/* Animate a number counting up with CSS @property */
@property --num {
  syntax: '<integer>';
  initial-value: 0;
  inherits: false;
}

.counter {
  --num: 0;
  animation: count-up 2s ease-out forwards;
  counter-reset: num var(--num);
  font-size: 3rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.counter::after {
  content: counter(num);
}

@keyframes count-up {
  to { --num: 1250; }
}

Magnetic Hover Effect

/* Element follows cursor position within its bounds */
document.querySelectorAll('.magnetic').forEach(el => {
  el.addEventListener('mousemove', (e) => {
    const rect = el.getBoundingClientRect();
    const x = e.clientX - rect.left - rect.width / 2;
    const y = e.clientY - rect.top - rect.height / 2;
    el.style.transform = `translate(${x * 0.3}px, ${y * 0.3}px)`;
  });

  el.addEventListener('mouseleave', () => {
    el.style.transform = 'translate(0, 0)';
    el.style.transition = 'transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275)';
  });

  el.addEventListener('mouseenter', () => {
    el.style.transition = 'none';
  });
});

Checklist for Microinteractions

• [ ] All interactive elements have hover/focus/active states
• [ ] Animations use transform and opacity (GPU-composited)
• [ ] Timing system defined with CSS custom properties
• [ ] Easing curves feel natural (no linear transitions on UI elements)
• [ ] Duration is appropriate: 150-400ms for most UI transitions
• [ ] prefers-reduced-motion is fully supported
• [ ] Loading states use skeleton screens or spinners
• [ ] Focus states are visible for keyboard navigation
• [ ] No animation blocks user interaction
• [ ] Animations are consistent across the product
• [ ] will-change used sparingly and removed after animation
• [ ] Page transitions are smooth (View Transitions API or JS)
• [ ] Performance tested on low-end devices

Resources

Inspiration

• UI Movement - Curated UI animation gallery
• Hover.css - Collection of CSS hover effects
• Easings.net - Visual easing function reference
• Cubic Bezier - Interactive easing curve tool

Libraries

• Framer Motion - React animation library
• GSAP - Professional JavaScript animation
• Lottie - After Effects animations for web
• Motion One - Lightweight animation library
• Animate.css - Pre-built CSS animations

Further Reading

• Animation at Work by Rachel Nabors - Principles of UI animation
• Designing Interface Animation by Val Head - Practical motion design
• An Interactive Guide to CSS Transitions - Josh Comeau
• Web Animation Performance Guide - web.dev