Principle	Accessible Implementation
Squash & Stretch	Opacity/color change instead
Anticipation	State change indication without motion
Staging	Focus management, not motion-based
Straight Ahead / Pose to Pose	Instant state changes
Follow Through / Overlapping	Eliminated or minimal fade
Slow In / Slow Out	Instant or very gentle ease
Arc	Straight or no movement
Secondary Action	Reduced or eliminated
Timing	Instant (0ms) or extended duration
Exaggeration	Removed entirely
Solid Drawing	Static visual clarity
Appeal	Clarity over personality

Core Principle

Animation should enhance understanding, never hinder it. When motion causes harm, provide alternatives that maintain functionality.

Respecting User Preferences

CSS Media Query

/* Default: Full animation */
.element {
    transition: transform 300ms ease-out;
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    .element {
        transition: opacity 200ms ease-out;
        /* Or no transition at all */
        transition: none;
    }
}

JavaScript Detection

const prefersReducedMotion = window.matchMedia(
    '(prefers-reduced-motion: reduce)'
).matches;

if (prefersReducedMotion) {
    // Use instant transitions or subtle fades
} else {
    // Use full animations
}

Principle Adaptations

Squash & Stretch → Replace with opacity or color changes. A button can darken on press instead of compressing. Loading indicators can pulse opacity instead of bouncing.

Anticipation → Use static indicators. Show a loading state immediately rather than animated preparation. Hover states change color instantly rather than scaling.

Staging → Use focus management and visual hierarchy. Scroll to content rather than animated reveals. Static highlighting over motion-based attention.

Motion Types → Instant state changes replace transitions. Toggle switches snap position. Modals appear instantly. Menus show without animation.

Follow Through → Eliminated. Elements reach final state immediately. No settling, bouncing, or overshoot effects.

Easing → Either instant (0ms) or very gentle, extended duration (500ms+) with minimal distance. If using motion, slow and subtle.

Arc/Paths → Straight movement only if any movement. Prefer opacity transitions over positional. No circular or complex motion paths.

Secondary Action → Significantly reduced or eliminated. Single, clear feedback per interaction. No cascading or staggered animations.

Timing → Two approaches: instant (0ms) for snappy feedback, or extended (500ms+) for gentle perception. Avoid 150-400ms range—fast enough to notice, slow enough to trigger symptoms.

Exaggeration → Removed entirely. Literal, proportional visual feedback only. No overshoots, bounces, or dramatic effects.

Solid Drawing → Maintain visual clarity in static states. Design must work without any animation. Strong contrast and clear hierarchy.

Appeal → Appeal through clarity, not personality. Clean, predictable interactions. User confidence in interface stability.

Safe Motion Patterns

Generally Safe

Opacity fades (keep subtle)
Color transitions
Small scale changes (<5%)
Very slow movement (500ms+)
Non-repeating animations

Potentially Harmful

Parallax scrolling
Background movement
Zoom animations
Spinning/rotating elements
Fast repeated animations
Large moving areas (>1/4 viewport)

Always Avoid

Auto-playing video backgrounds
Infinite animations
Vestibular-triggering patterns
Flashing (seizure risk)
Rapid zoom in/out

WCAG Guidelines

WCAG 2.1 Success Criteria

2.3.3 Animation from Interactions (AAA) Motion triggered by interaction can be disabled unless essential.

2.2.2 Pause, Stop, Hide (A) Moving content lasting >5 seconds must be pausable.

2.3.1 Three Flashes (A) No content flashes more than 3 times per second.

Implementation Checklist

Testing

Enable reduced motion in OS settings
Verify all functionality works
Check all states are clearly communicated
Ensure no motion remains that should be reduced
Test with screen reader users
Validate with vestibular disorder users if possible

accessible-motion

Accessible Motion Design

Quick Reference