> Semantic HTML helps here too. Proper structural boundaries allow for more effective use of modern CSS containment strategies:

> contain: layout; tells the browser it doesn’t need to recalculate layout outside the element.

> will-change: transform; hints that a compositing layer is needed.

> isolation: isolate; and contain: paint; can help prevent visual spillover and force GPU layers.

That sounds like some powerful optimization strategies! I'll need to research these. Favoriting this article for later reference...