Rendering Content Visibility

## CSS content-visibility for Long Lists Apply `content-visibility: auto` to defer off-screen rendering. **CSS:** ```css .message-item { content-visibility: auto; contain-intrinsic-size: 0 80px; } ``` **Example:** ```tsx function MessageList({ messages }: { messages: Message[] }) { return ( ) } ``` For 1000 messages, browser skips layout/paint for ~990 off-screen items (10× faster initial render).