Visual stability protects user intent, not merely appearance

Unexpected layout shifts can move controls beneath a pointer, causing mistakes rather than merely visual annoyance.

Images without dimensions, late advertisements, injected content, and font changes commonly displace visible interface elements.

CLS measures unexpected movement through impact and distance, aggregated within defined session windows.

A low score still cannot prove coherent layout, accessible reading order, or correct interaction design.

If loading controls geometry, then responsive feedback preserves intent during consequential actions.

Stable geometry protects user intent, especially during forms, purchases, navigation, and other consequential actions.

Reserve space for asynchronous content, avoid disruptive insertion, and inspect field shifts that laboratory scripts miss.