Sections
The 10 rule categories: heading order = audit priority. Rule files are named <prefix>-<slug>.md. _template.md scaffolds new rule files and is not loaded during an audit.
Category impact is the impact of the category's worst-case rules, not an average. A rule's own frontmatter impact is the authoritative value and often differs from its category, so report findings with the rule-level value. The rules that most diverge from their category are brand-color and brand-licensing (HIGH inside MEDIUM), pairing-ui-fonts (HIGH inside MEDIUM), opentype-tabular-figures (HIGH inside MEDIUM), punct-daggers and punct-midpoints (LOW-MEDIUM inside CRITICAL), and font-rendering (MEDIUM inside CRITICAL).
Counts must reconcile with ls rules/ | grep -v '^_' | wc -l (total: 78).
1. Font Selection & Weights (font), 11 rules
CRITICAL. Faux bold and italic, broken @font-face mappings, and missing fallback stacks make text render wrong or not at all. Also covers weight, width, optical size, and font quality.
2. Sizing & Measure (size), 6 rules
CRITICAL. Body size, line height, and measure decide whether the text is readable at all, and a fixed-px line height inherited by a heading overlaps lines outright. Also covers responsive scaling and emphasis.
3. Punctuation & Special Characters (punct), 12 rules
CRITICAL. The most visible sign of amateur typography: straight quotes, double hyphens for dashes, and missing diacritics are non-negotiable in rendered copy. The rest of the category (footnote marks, symbols, fractions, separators) is refinement, priced MEDIUM and below per rule.
4. Spacing & Rhythm (spacing), 8 rules
HIGH. Letterspaced body text, cramped gutters, and text touching a phone bezel cost readability directly. Uppercase tracking, subhead proximity, and paragraph separation control rhythm.
5. Hierarchy & Scale (hierarchy), 8 rules
MEDIUM-HIGH. Size contrast, weight variation, and shallow semantic heading levels make content scannable and navigable by screen reader. Body first; headings derive from it.
6. Alignment & Layout (layout), 6 rules
MEDIUM. Justified text without hyphenation and centered body copy break the left reading edge; list markup, proximity, and widow control affect page-level readability.
7. OpenType Features (opentype), 7 rules
MEDIUM. Mostly refinement, since browsers enable kern and liga by default. The exceptions carry real cost: misaligned figures in a data table, and ligatures inside code blocks that obscure individual characters.
8. Brand & Identity (brand), 8 rules
MEDIUM. Mostly consistency and recognition, but this is where the WCAG contrast floor (brand-color) and font licensing exposure (brand-licensing) live, both HIGH.
9. Typeface Pairing (pairing), 5 rules
MEDIUM. Combine typefaces by matching stress and skeleton, by deliberate contrast, or via superfamilies; same-category pairs read as accidents. pairing-ui-fonts is HIGH: ambiguous l/I/1 glyphs cause real data-entry errors.
10. Display & Headlines (display), 7 rules
LOW-MEDIUM. Headline spacing, drop caps, swashes, lead paragraphs, and headline-specific OpenType features add polish to large type.