What is Cumulative Layout Shift?
Cumulative Layout Shift (CLS) is a Core Web Vitals metric Google uses to measure the visual stability of a webpage. You should keep it at 0.1 or less.
Text, images, and videos shift around as a webpage loads. This could occur when a font changes size or an image or video appears on the page.
While this shifting would cause some discomfort to a visitor reading a page, it can also lead to visitors clicking on buttons and links they never intended to click.
To reduce the chances of these sorts of content appearing in searches, Google introduced the Cumulative Layout Shift metric. The metric measures the largest shift that occurs when a visitor is on a webpage.