Support content reflow at 400% zoom

Users with low vision zoom to 400% to read content—horizontal scrolling at that level makes it impossible to track lines of text and navigate effectively.

Quick Reference

• Content must reflow to single column at 400% zoom (1280px width at 320px equivalent)
• No horizontal scrolling required to read content
• All functionality must remain accessible at high zoom levels
• Use relative units and fluid layouts that adapt to viewport

Check

Zoom the browser to 400% and verify content reflows to a single column without horizontal scrolling, truncation, or overlapping elements. Test all interactive features remain functional at this zoom level.

Fix

Use responsive CSS with relative units (rem, em, %) instead of fixed pixels. Implement fluid layouts that adapt to viewport width. Test with CSS media queries to ensure layouts reflow gracefully.

Explain

Explain how users with low vision rely on browser zoom up to 400% to read content, and why horizontal scrolling creates significant barriers for users who can only see a small portion of the screen at once.

Code Review

Review the rendered markup and interactive states that affect Support content reflow at 400% zoom. Flag exact elements, roles, labels, focus behavior, or keyboard interactions that violate the rule, and note how to verify the fix with browser accessibility tooling or assistive tech.

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For full implementation details, code examples, and framework-specific guidance, see references/rule.md.

Rule page: https://frontendchecklist.io/en/rules/accessibility/zoom-reflow