Next.js Layout Shift on Mobile Devices
Your v0-generated Next.js application suffers from significant cumulative layout shift (CLS) on mobile devices. Page content jumps around as elements load, fonts swap, images resize, and dynamic content pushes other elements out of position. Users on mobile devices struggle to tap buttons and links as the layout shifts beneath their fingers.
CLS is one of Google's Core Web Vitals and directly impacts your search ranking. Mobile devices are especially affected because the narrower viewport amplifies the visual impact of any layout instability.
V0 often generates layouts that look stable on desktop but rely on content-dependent sizing that causes significant reflow on mobile screens as assets load progressively.
Error Messages You Might See
Common Causes
- Images without dimensions — img tags or Image components missing width/height cause reflow when images load
- Font loading without size-adjust — custom fonts loading after initial render cause text to reflow
- Dynamic content injection — client-side data fetching inserts content that pushes existing elements down
- CSS not mobile-optimized — desktop-first styles that reflow dramatically at mobile breakpoints
- Third-party scripts — ads, analytics, or chat widgets injecting elements after page load
How to Fix It
- Set explicit dimensions on media — always provide width and height on Image components or use aspect-ratio CSS
- Use next/font — replace external font loading with next/font for automatic size-adjust and font-display optimization
- Reserve space for dynamic content — use min-height or skeleton placeholders for content loaded via useEffect or SWR
- Add loading skeletons — implement Suspense boundaries with skeleton UI that matches the final layout dimensions
- Test with Lighthouse — run Lighthouse in mobile mode and address each CLS source identified in the report
- Use CSS contain — add
contain: layoutto sections that load independently to prevent cascading layout shifts
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Get HelpFrequently Asked Questions
What is a good CLS score?
Google considers CLS below 0.1 as good, 0.1-0.25 as needs improvement, and above 0.25 as poor. Measure using Lighthouse or PageSpeed Insights in mobile mode.
How do I find what causes layout shift?
Open Chrome DevTools > Performance tab > check 'Layout Shifts' in the experience section. Each shift is highlighted with the affected element.
Does next/font fix all font-related CLS?
next/font automatically applies size-adjust and font-display: swap, eliminating most font-related layout shifts. It also preloads fonts for faster delivery.