Perceivable
WCAG 1.4.12
Text Spacing
No loss of content when users override line height to 1.5×, paragraph spacing to 2×, letter spacing to 0.12em, and word spacing to 0.16em. Tests low-vision user overrides.
In plain terms
If someone widens the spacing between lines or letters to read more easily, nothing on the page should overlap or get cut off.
Why this matters
People with dyslexia and low vision often increase spacing to read more comfortably. If your layout breaks when they do, you've removed the very adjustment they depend on.
How to detect
Quick check
Apply a text-spacing bookmarklet (line height 1.5, paragraph 2×, letter 0.12em, word 0.16em). Check nothing overlaps, is cut off, or disappears.