CSS Animation Reference

Master Modern Web Motion

A performance-first, accessibility-aware reference for modern CSS animation and motion architecture. From compositor-only properties to scroll-driven timelines — built for frontend engineers who ship at 60fps.

Modern web animation is no longer about adding movement for aesthetics — it's a rendering pipeline engineering discipline. Every keyframe touches the browser's compositor, and every misplaced width transition burns precious milliseconds on the main thread. This reference maps the full stack: from CSS declaration to GPU layer, from @keyframes architecture to prefers-reduced-motion governance.

The content is organised into four interconnected areas — rendering fundamentals, modern view-transition and scroll APIs, performance budgeting, and accessible motion — spanning more than eighty pages across twenty topic hubs. Each area provides an overview for foundational concepts, focused hubs for each mechanism, and deep-dive guides with auditable code examples. Every code block includes a @media (prefers-reduced-motion: reduce) fallback — non-negotiable for production-grade motion systems.

Whether you're debugging jank with Chrome DevTools' Layers panel, designing scroll-driven reveal effects with animation-timeline: view(), or enforcing a strict 16.67ms frame budget across a monorepo, you'll find actionable, compositor-aware guidance here.

Where each area of this reference sits in the frameThe four areas map onto consecutive stages of the browser's rendering pipeline — which is why they are organised this way.Where each area of this reference sits in the frameStylefundamentalsLayoutwhat to avoidPaintinvalidationCompositethe targetDisplay60 fps
The four areas map onto consecutive stages of the browser's rendering pipeline — which is why they are organised this way.
Four Content Areas

Everything You Need to Ship Fluid Motion

From rendering fundamentals to cutting-edge browser APIs to accessible-by-default motion — structured for engineers at every level.

Core CSS Animation Fundamentals

Master the rendering pipeline beneath every CSS animation. Compositor threads, frame budgets, cubic-bezier mathematics, hardware-accelerated properties, and state machine patterns for predictable motion.

Modern View Transitions & Scroll APIs

Harness the View Transitions API, scroll-driven animation timelines, @starting-style entry effects, and container query motion triggers — all running on the compositor thread at 60fps.

Performance Budgeting & GPU Architecture

Enforce strict 16.67ms frame budgets, audit layer promotion strategies, apply CSS containment, and manage will-change lifecycles via IntersectionObserver to maximise GPU efficiency.

Accessible Motion Architecture

Build motion that respects prefers-reduced-motion, vestibular safety, and WCAG 2.2 conformance by design — a two-layer reduced-motion cascade, safe durations and thresholds, and accessible focus and state motion.

Site Features

Built for Developers

Syntax-Highlighted Code

Every code block uses a Colorful Daybreak light theme with a one-click copy button.

Accessibility First

All animations include prefers-reduced-motion fallbacks. No exceptions.

Hand-Authored SVG Diagrams

Rendering-pipeline and architecture diagrams drawn as inline SVG, theme-aware and styled to match the design system.

PWA Ready

Installable on Android, iOS, and desktop. Works offline with smart caching strategies.

Compositor-Aware

Only transform and opacity are animated in the UI. GPU-first by design.

Breadcrumb Navigation

Hierarchical breadcrumbs and scroll-offset-aware anchor links on every content page.