Image strategy, font loading, and animation choices that decide whether you pass or fail.
Largest Contentful Paint is almost always an image problem. Serve the hero at the size it renders, preload it, and never animate it in from opacity zero.
Cumulative Layout Shift comes from fonts and late-loading embeds. Reserve space for anything asynchronous, and match fallback font metrics to the web font.
Interaction latency is usually scroll-linked animation running on the main thread. Prefer transform and opacity, keep observers cheap, and cut effects on reduced-motion preferences.