Why is my CLS value poor even though the page loads quickly?

CLS (Cumulative Layout Shift) is independent of loading speed. It measures how much page elements shift after initial rendering. Common causes of a high CLS value include: images and videos without defined dimensions (width/height), late-loaded web fonts causing a Flash of Unstyled Text, dynamically inserted ad banners or cookie consent layers that push page content, and CSS animations that modify layout properties instead of transforms. In our performance analysis, we identify the specific CLS culprits and address them systematically.