Success Criterion 1.4.10
Conformance level AA

Floating Chat Widget Blocking Content at Mobile Width

1.4.10 — Reflow

Scenario

Setting

A used-car marketplace's listing filter

What’s wrong

Chat widgets/floating buttons overlapping and blocking content at 320px.

Example

.layout { width: 1200px; }

Why it matters

Low-vision users at high zoom and people reading on narrow mobile viewports.

How to test

Set the viewport to 320px and check floating chat widgets/buttons: if they overlap and block page content with no way to dismiss or reposition them, it fails.

How to fix

At 320 CSS px width (400% zoom on a 1280px desktop), content must reflow into one column with only vertical scrolling and nothing missing or unreachable. .layout { max-width: 1200px; width: 100%; } Content must reflow into one column at 320px wide with no horizontal scrolling and nothing missing.

Outcome

On a used-car marketplace's listing filter, this barrier is gone for low-vision users at high zoom and people reading on narrow mobile viewports — they can complete the task without hitting this wall.

Who is affected