CLS IS THE NEW PAGE SPEED: WHY DESIGNERS NEED TO CARE MORE THAN DEVELOPERS

Summary from the TLDR Design newsletter

Cumulative Layout Shift (CLS), a Core Web Vital that measures visual stability, has become a critical UX metric that designers must address, not just developers. Modern design decisions, such as undefined image heights, custom fonts without fallbacks, and unplanned dynamic content, directly cause layout shifts that frustrate users and harm search rankings. Designers need to adopt CLS-conscious workflows by reserving space for loading content, planning font fallback behavior, and creating stable layouts that survive real-world loading conditions.