FontBlacklistApplied [check] v1.0.0

Detects blacklisted default font-families (Arial, Helvetica, Times New Roman, Comic Sans, Papyrus, Courier New) used as PRIMARY font, and detects sites that load no custom fonts at all (signaling lack of typographic care).

signature: (css: string, html: string, context?: object) -> CheckResult predicate: // Blacklisted font-family stacks (signal "AI default" aesthetic): BLACKLIST = [ 'Comic Sans MS', 'Papyrus', 'Times New Roman', // raw — system Times is fine, Times New Roman explicit is dated 'Arial', // when used alone without sans-serif fallback chain 'Helvetica', // when used alone — modern stacks use Inter/SF 'Courier New', ] // Also blacklist: any -apple-system-only stack with no custom font (signals "no design taste") fontDecls = parseCSS(css).filter(d => d.property === 'font-family' || d.property === 'font') for d in fontDecls: stack = parseFontStack(d.value) for f in stack.fonts: for bad in BLACKLIST: if f.toLowerCase() === bad.toLowerCase(): // Check if it's only the fallback (last in stack) — that's allowed if stack.fonts.indexOf(f) === 0: yield { selector: d.selector, value: d.value, fail: 'blacklisted-primary-font', font: f }

// Detect "no @font-face declared anywhere" → site relies on system defaults only hasFontFace = /@font-face\s*{/.test(css) hasGoogleFonts = /fonts.googleapis.com|fonts.bunny.net/.test(html) hasLocalFonts = /url(['"]?[^)]*.(woff2?|ttf|otf)/.test(css) if !hasFontFace && !hasGoogleFonts && !hasLocalFonts: yield { fail: 'no-custom-font-loaded', remedy: 'Load a custom display + body font pair' }

Validates

@community/rule-font-blacklist-applied

Severity

medium

Failure Message Template

Selector '{selector}' uses blacklisted primary font '{font}' (declaration: {value}). Replace with a custom display/body pair (e.g. Inter + Source Serif, or Geist + Newsreader).

Evaluation Method

automated

Tools

• regex
• postcss
• @anthropic/claude-code

False Positive Rate

low

FontBlacklistApplied [check] v1.0.0

Detects blacklisted default font-families (Arial, Helvetica, Times New Roman, Comic Sans, Papyrus, Courier New) used as PRIMARY font, and detects sites that load no custom fonts at all (signaling lack of typographic care).

signature: (css: string, html: string, context?: object) -> CheckResult predicate: // Blacklisted font-family stacks (signal "AI default" aesthetic): BLACKLIST = [ 'Comic Sans MS', 'Papyrus', 'Times New Roman', // raw — system Times is fine, Times New Roman explicit is dated 'Arial', // when used alone without sans-serif fallback chain 'Helvetica', // when used alone — modern stacks use Inter/SF 'Courier New', ] // Also blacklist: any -apple-system-only stack with no custom font (signals "no design taste") fontDecls = parseCSS(css).filter(d => d.property === 'font-family' || d.property === 'font') for d in fontDecls: stack = parseFontStack(d.value) for f in stack.fonts: for bad in BLACKLIST: if f.toLowerCase() === bad.toLowerCase(): // Check if it's only the fallback (last in stack) — that's allowed if stack.fonts.indexOf(f) === 0: yield { selector: d.selector, value: d.value, fail: 'blacklisted-primary-font', font: f }

// Detect "no @font-face declared anywhere" → site relies on system defaults only hasFontFace = /@font-face\s*{/.test(css) hasGoogleFonts = /fonts.googleapis.com|fonts.bunny.net/.test(html) hasLocalFonts = /url(['"]?[^)]*.(woff2?|ttf|otf)/.test(css) if !hasFontFace && !hasGoogleFonts && !hasLocalFonts: yield { fail: 'no-custom-font-loaded', remedy: 'Load a custom display + body font pair' }

Validates

@community/rule-font-blacklist-applied

Severity

medium

Failure Message Template

Selector '{selector}' uses blacklisted primary font '{font}' (declaration: {value}). Replace with a custom display/body pair (e.g. Inter + Source Serif, or Geist + Newsreader).

Evaluation Method

automated

Tools

• regex
• postcss
• @anthropic/claude-code

False Positive Rate

low

Validates

@community/rule-font-blacklist-applied

Severity

medium

Failure Message Template

Selector '{selector}' uses blacklisted primary font '{font}' (declaration: {value}). Replace with a custom display/body pair (e.g. Inter + Source Serif, or Geist + Newsreader).

Evaluation Method

automated

Tools

• regex
• postcss
• @anthropic/claude-code

False Positive Rate

low