---
title: "Content overflows horizontally at 320px (a11y/reflow-overflow)"
description: "a11y/reflow-overflow: WCAG 1.4.10 requires content to reflow at 320 CSS px (equivalent to 400% zoom) without horizontal scrolling; overflow also breaks…"
canonical: https://void-design.vercel.app/rules/a11y/reflow-overflow
lastModified: 2026-09-16
---

# Content overflows horizontally at 320px

`a11y/reflow-overflow` · severity **warn** · category Accessibility · detected by `void a11y` and `void audit`

## Why it matters

WCAG 1.4.10 requires content to reflow at 320 CSS px (equivalent to 400% zoom) without horizontal scrolling; overflow also breaks mobile layouts.

## How to fix it

Find the element wider than the viewport (fixed widths, long unbroken strings, wide tables/code) and let it shrink: max-width: 100%, min-width: 0 in flex/grid children, overflow-wrap: anywhere, or a scroll container for tables.

## Example

```
img, video, pre, table { max-width: 100%; }
.flex > * { min-width: 0; }
```

## References

- https://www.w3.org/WAI/WCAG22/Understanding/reflow

## More accessibility rules

`void a11y` reports 48 rules in this category. WCAG 2.2 AA through axe-core, plus checks axe can't do alone: visible keyboard focus, 24/44px target size on mobile, 320px reflow and disabled zoom.

- `link-in-text-block` Links in text are distinguished only by color — [a11y/link-in-text-block](https://void-design.vercel.app/rules/a11y/link-in-text-block)
- `autocomplete-valid` Invalid autocomplete value — [a11y/autocomplete-valid](https://void-design.vercel.app/rules/a11y/autocomplete-valid)
- `meta-viewport` Zooming is disabled — [a11y/meta-viewport](https://void-design.vercel.app/rules/a11y/meta-viewport)
- `bypass` No way to skip repeated content — [a11y/bypass](https://void-design.vercel.app/rules/a11y/bypass)
- `video-caption` Video has no captions — [a11y/video-caption](https://void-design.vercel.app/rules/a11y/video-caption)
- `axe-other` Other axe-core accessibility violation — [a11y/axe-other](https://void-design.vercel.app/rules/a11y/axe-other)
- `target-size` Touch target is smaller than 24×24 px — [a11y/target-size](https://void-design.vercel.app/rules/a11y/target-size)
- `focus-not-visible` Keyboard focus is not visible — [a11y/focus-not-visible](https://void-design.vercel.app/rules/a11y/focus-not-visible)

Detected by `void a11y` and `void audit`. Explain it in a terminal: `void rules a11y/reflow-overflow`