Why it matters
Small body text on phones is hard to read and causes pinch-zooming; iOS also zooms into inputs under 16px.
How to fix it
Use 16px (1rem) body text on mobile and ≥ 16px for inputs.
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-longBody text lines are too longline-length-shortBody text lines are very short on desktopbody-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