Offer a control that opens up line spacing
G188 adds a button or link that opens up the spacing of the text. W3C's test sets two thresholds and requires both. Line height goes to at least 1.5, and paragraph spacing goes to at least 1.5 times the line spacing, which is a ratio against the leading rather than against the font size. The control itself has to be labeled. W3C's worked example is a stylesheet setting line-height to 1.5 with a 2em bottom margin on paragraphs, switched in by the control. W3C lists this as sufficient for 1.4.8 Visual Presentation, at Level AAA. It is not one of the two techniques W3C names for the Level AA text spacing rule, and those two are about surviving spacing the reader sets rather than about offering spacing yourself. W3C's named audience here is people with cognitive disabilities, who often struggle with single-spaced text.
How we find it in an audit
Our reviewers use the control and then measure what changed. Line height alone is a half-fix, because paragraph spacing is the other half of the test. Then we look for containers that break, since opening up spacing makes text taller and a fixed-height box will clip it. We check the preference survives across pages too.
How affected users experience it
Tightly set text is hard to track for readers with dyslexia, for people with low vision, and for anybody whose eyes lose the line and land on the wrong one. Opening the spacing gives each line its own space to sit in, which is why people who need it need it on every page rather than on one. A control that resets on navigation solves the demo and not the problem.
Passes vs. fails
Passes
A 'Comfortable spacing' toggle raises line height to 1.5 and paragraph spacing well beyond it, and every container grows to fit.
Fails
Article text locked at line-height 1.1 with no spacing control, and containers that clip when a reader forces spacing through a browser extension.
Other ways to satisfy this rule
21 guides on this site are filed under 1.4.8 Visual Presentation. W3C lists this one as sufficient for that rule on its own. Implement it correctly, in a way your readers' software actually supports, and the rule is met.
- C12sufficientSize text in percent so it scales
- C13sufficientUse named font sizes that respect user defaults
- C14sufficientSize text in em units, not pixels
- C19sufficientAlign text left or right, never justified
- C20sufficientCap line length with relative column widths
- C21sufficientGive paragraphs breathing room with line spacing
This guide is our interpretation of W3C technique G188: Providing a button on the page to increase line spaces and paragraph spaces. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.