Reduce CLS and Layout Shifts

CLS is not strictly a speed metric. It measures how comfortable and predictable a page feels while a visitor uses it.

If elements slide, jump, move, or shift during normal browsing, the page provides a poor experience.
Even an automatically advancing slider can be frustrating when it moves content without the visitor requesting it.

A layout change caused by a user action should happen within 0.5 seconds of the click. In that case, the shift is expected and is not treated as an unexpected layout change.

CLS is commonly evaluated together with performance metrics, so it is also included in the speed audit.