CSS··8 min read

CSS Animations & Transitions — Smooth UI Motion

CSS transition and @keyframes animation guide. Transform, opacity, and performance best practices.

CSS animationscss transitionscss transform

CSS Transitions and Keyframe Animations

Subtle motion guides attention — button hovers, modal entrances, loading states. CSS transitions handle simple state changes; @keyframes handle complex sequences.

Why CSS animations Matters

Motion communicates state changes — but only transform and opacity animations stay on the GPU compositor thread for 60fps performance.

Use transition for hover/focus state changes; reserve @keyframes for loaders and multi-step entrance effects.

CSS animations — Key Ideas You Must Know

  • transition: property duration easing
  • transform and opacity are GPU-friendly
  • @keyframes for looping animations
  • prefers-reduced-motion for accessibility
  • Avoid animating width/height (use transform)

Practice CSS animations with Free Lessons

Try the CSS transitions lesson on Sturdee and animate a card hover effect.

Tip: Free interactive lesson: /tutorials/css/css_transitions — practice CSS animations with runnable code on Sturdee.

CSS Animations & Transitions — FAQ

Frequently Asked Questions

CSS or JavaScript animation?+

CSS for simple UI transitions. JavaScript (or libraries) for complex choreographed sequences.