Why it matters
Beyond ~75-85 characters per line the eye loses its place returning to the next line; reading slows down.
How to fix it
Constrain prose containers to ~60-75ch (max-width: 65ch or a --container-prose token).
Example
.prose { max-width: 65ch; }More design rules
void design reports 19 rules in this category. Measured design heuristics from computed styles: font families, type scale, line length, palette and accent sprawl, spacing grid, radius sprawl, dark mode and the tells of generated UI.
too-many-font-familiesToo many font familiesno-type-scaleToo many distinct font sizes (no type scale)line-length-shortBody text lines are very short on desktopbody-text-smallBody text is smaller than 15px on mobilebody-line-height-tightBody line-height is too tightheading-trackingLarge headings use default letter-spacingheading-no-balanceHeadings do not use text-wrap: balancepalette-sprawlToo many distinct colors