How to test
Zoom & Reflow
Low-vision users zoom in — a lot. Test that content reflows to a single column with no horizontal scrolling, nothing is clipped or overlapping, and user text-spacing overrides don't break the layout.
What to test
- At 200% browser zoom, all text and functionality remains available.
- At 320 CSS px wide (≈ 400%), content reflows to one column with no two-dimensional scrolling.
- No content is clipped, truncated, or overlapping when enlarged.
- Sticky headers/footers don't cover the content or the focused element.
- User text-spacing overrides (line/letter/word/paragraph) don't cut text off.
- The page works in both portrait and landscape orientation.
How to test
- 1Zoom the browser to 200% and confirm nothing is lost or needs horizontal scrolling to read.
- 2Set the viewport to 320px wide (or zoom to 400%) and confirm content reflows to a single column.
- 3Apply a text-spacing bookmarklet and confirm no text is clipped or overlapping.
- 4Rotate between landscape and portrait and confirm layout and functionality hold.
Common failures
- Fixed-width containers that force horizontal scrolling when zoomed.
- Text sized so it doesn't scale, or content that overflows its box.
- Two-dimensional scrolling of a region that could reflow.
- Content locked to a single orientation.
- overflow:hidden clipping text when line-height increases.