TypographyWeightBlacklist [constraint] v1.0.0

font-weight 100, 200, and 300 are BANNED for body text (≤ 20px) and primary UI labels; font-weight 900 is BANNED for body text. Permitted body/label weights are 400 (regular), 500 (medium), and 600 (semibold). Weight 700 (bold) is permitted for headings only. Weight 800–900 is permitted for display/hero text only.

Target

font-weight values for body prose and primary UI text

Severity

high

Meta

• License: Apache-2.0
• License Provenance: package-authorship-claim

Values

• • Weight: 100
  • Name: Thin
  • Body Use: BANNED
  • Heading Use: BANNED
  • Display Use: BANNED
• • Weight: 200
  • Name: ExtraLight
  • Body Use: BANNED
  • Heading Use: BANNED
  • Display Use: decoration-only
• • Weight: 300
  • Name: Light
  • Body Use: BANNED
  • Heading Use: warn
  • Display Use: allowed
• • Weight: 400
  • Name: Regular
  • Body Use: REQUIRED-default
  • Heading Use: allowed
  • Display Use: allowed
• • Weight: 500
  • Name: Medium
  • Body Use: allowed
  • Heading Use: allowed
  • Display Use: allowed
• • Weight: 510
  • Name: SemiBold+
  • Body Use: emphasis-only
  • Heading Use: PREFERRED
  • Display Use: allowed
• • Weight: 700
  • Name: Bold
  • Body Use: emphasis-inline-only
  • Heading Use: allowed
  • Display Use: allowed
• • Weight: 800
  • Name: ExtraBold
  • Body Use: BANNED
  • Heading Use: warn-verify-rendering
  • Display Use: allowed
• • Weight: 900
  • Name: Black
  • Body Use: BANNED
  • Heading Use: BANNED
  • Display Use: allowed-hero-only

Approved Alternatives

• Use weight 400 for body prose as default.
• Use weight 500–600 for UI labels needing slight emphasis.
• Use weight 700 for headings where bold differentiation is needed.
• Use weight 800–900 only for hero/display text at 48px+ where stroke weight is visually substantial.

TypographyWeightBlacklist [constraint] v1.0.0

font-weight 100, 200, and 300 are BANNED for body text (≤ 20px) and primary UI labels; font-weight 900 is BANNED for body text. Permitted body/label weights are 400 (regular), 500 (medium), and 600 (semibold). Weight 700 (bold) is permitted for headings only. Weight 800–900 is permitted for display/hero text only.

Target

font-weight values for body prose and primary UI text

Severity

high

Meta

• License: Apache-2.0
• License Provenance: package-authorship-claim

Values

• • Weight: 100
  • Name: Thin
  • Body Use: BANNED
  • Heading Use: BANNED
  • Display Use: BANNED
• • Weight: 200
  • Name: ExtraLight
  • Body Use: BANNED
  • Heading Use: BANNED
  • Display Use: decoration-only
• • Weight: 300
  • Name: Light
  • Body Use: BANNED
  • Heading Use: warn
  • Display Use: allowed
• • Weight: 400
  • Name: Regular
  • Body Use: REQUIRED-default
  • Heading Use: allowed
  • Display Use: allowed
• • Weight: 500
  • Name: Medium
  • Body Use: allowed
  • Heading Use: allowed
  • Display Use: allowed
• • Weight: 510
  • Name: SemiBold+
  • Body Use: emphasis-only
  • Heading Use: PREFERRED
  • Display Use: allowed
• • Weight: 700
  • Name: Bold
  • Body Use: emphasis-inline-only
  • Heading Use: allowed
  • Display Use: allowed
• • Weight: 800
  • Name: ExtraBold
  • Body Use: BANNED
  • Heading Use: warn-verify-rendering
  • Display Use: allowed
• • Weight: 900
  • Name: Black
  • Body Use: BANNED
  • Heading Use: BANNED
  • Display Use: allowed-hero-only

Approved Alternatives

• Use weight 400 for body prose as default.
• Use weight 500–600 for UI labels needing slight emphasis.
• Use weight 700 for headings where bold differentiation is needed.
• Use weight 800–900 only for hero/display text at 48px+ where stroke weight is visually substantial.

Relations

related: [@community/anti-pattern-thin-weight-body, @community/rule-body-readability, @community/check-body-readability]

Rationale

Weights 100–300 render as hairlines at body sizes on 1×/1.5× displays and fail WCAG 1.4.3 contrast when combined with muted text colors. Weight 900 in body prose creates an aggressive, over-emphatic tone that undermines reading comfort. The permitted range 400–700 covers all readable typographic variation without sacrificing accessibility or aesthetics.