Line Height Below 1.3 Is Unreadable
MUST: Set body `line-height` to 1.5–1.7 and never below 1.3 (flagged on any non-heading carrying more than 50 characters); derive the whole spacing scale from the resulting line box (16px × 1.5 = 24px).
Set body line-height between 1.5 and 1.7, and derive the spacing scale from it
Bad
Good
Why it matters
When lines sit too close, the descenders of one collide with the ascenders of the next and the eye can no longer isolate a single line, so it re-reads. impeccable's detector flags any non-heading element carrying more than 50 characters where lineHeight / fontSize falls below 1.3. The payoff of getting this right is structural, not just cosmetic: the body line box is the base unit of vertical rhythm, so 16px x 1.5 = 24px, and every margin, gap, and section break becomes a multiple of that one number instead of an arbitrary guess.