WCAG 1.4.10 · Level AA
What is WCAG reflow and how do I meet it?
Content must reflow into a single column without horizontal scrolling at 320 CSS pixels wide (equivalent to 400% zoom on a 1280px screen). WCAG 1.4.10 (Level AA) forbids two-dimensional scrolling except for content that genuinely needs it, like data tables.
What it is
Reflow is the ability of a layout to adapt to small viewports or high zoom without losing content or requiring horizontal scroll.
Why it matters
People with low vision zoom in heavily. If the layout forces horizontal scrolling, reading becomes painfully slow.
How to fix it
- 01Design layouts that collapse to a single column at narrow widths.
- 02Use relative units and flexible grids rather than fixed pixel widths.
- 03Reserve horizontal scroll only for content that requires it, such as wide tables.
How Aulys catches it
Aulys checks that your frames define responsive behavior that survives 320px / 400% zoom without clipping or horizontal scroll.
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