Use Transform & Opacity for Animations

Animating top or left forces layout recalculation. Instead:

.box {
 transform: translateX(200px);
 opacity: .8;
}

Use will-change Carefully

Tell the browser what you plan to animate so it can prepare GPU layers:

.box:hover {
 will-change: transform, opacity;
}

Prefer CSS Animation Over JS When Possible

CSS animations run off the main thread when implemented correctly.

Reduce DOM Reflows

• Avoid changing dimensions repeatedly
• Batch style changes together
• Use requestAnimationFrame() when animating via JS

A little optimisation goes a long way for smooth UI interactions.