Blocks of text should be easy to read (spacing, line length, justification)
Rule
visual-presentation· Document, language & navigation · impact minor · Live only (static → incomplete)
Why it matters
SC 1.4.8 (AAA) asks that blocks of text stay readable for people with low vision and reading disabilities: lines no wider than 80 characters, text not fully justified (the uneven "rivers" of white space in justified text disrupt tracking), and line spacing of at least 1.5. This rule checks rendered text blocks (paragraphs, list items, definitions, block quotes with substantial prose) against those three measurable requirements. Justification and line-height are only visible when declared on the element itself (the captured computed-style snapshot carries neither property), so a clean result is not proof of conformance; line length is estimated from the rendered block width and font size (average character ≈ 0.5em). Reports are capped at 10 blocks per page. Needs a live scan.
How to fix
Use text-align: left (or right for RTL) instead of justify; set line-height to 1.5 or more on body text; and constrain text columns (e.g. max-width: 36em) so lines stay at or under 80 characters. Also let users select foreground/background colors and resize text to 200% without horizontal scrolling — those parts of 1.4.8 need manual review.
Example
<p style="text-align:justify;line-height:1.1">Long runs of fully justified, tightly leaded paragraph text like this are measurably harder to track line-by-line for readers with low vision or dyslexia, because the stretched word spacing forms distracting rivers of white space.</p>
<p style="line-height:1.6;max-width:36em">Comfortably leaded, left-aligned paragraph text in a constrained column keeps each line short enough to track easily, which is exactly what the visual-presentation success criterion asks of long-form body copy.</p>
WCAG success criteria
1.4.8 Visual Presentation — Level AAA
Blocks of text must stay readable for people with low vision or reading disabilities: user-selectable colors, lines no wider than 80 characters, text not fully justified, at least 1.5 line spacing, and 200% text resize without horizontal scrolling.
Standards
This rule contributes to the following standards:
WCAG AAA