NoPureWhiteBg [constraint] v1.0.0

Backgrounds for long-form prose must not be pure white (#ffffff). Use a warm or cool off-white such as #f9f7f4 or oklch(98% 0.008 var(--hue)) to reduce halation and reading fatigue.

Target

• page background in long-form reading contexts
• article body background
• editorial / blog / marketing prose surfaces

Severity

high

Values

• • Forbidden: #ffffff
  • Forbidden Equivalent: rgb(255, 255, 255)
• • Forbidden: white
  • Forbidden Equivalent: oklch(100% 0 0)

Exceptions

• Cards / modals / tooltips where surface contrast against page background is the design intent.
• Dashboard data surfaces where pure white maximises legibility for tabular numerics.
• Print stylesheets — paper is the medium.

Approved Alternatives

• #f9f7f4 — warm paper-white (Atlantic / Readwise)
• oklch(98% 0.008 var(--hue)) — hue-aware off-white
• #fafaf7 — neutral off-white (Stripe long-form docs)
• #f5f5f4 — Tailwind stone-100

Enforcement

Stylelint custom rule rejecting background: #fff / background: white on selectors body, article, [role=main], .prose. Token review: --bg and --surface-page must not resolve to pure white in prose-context themes.

NoPureWhiteBg [constraint] v1.0.0

Backgrounds for long-form prose must not be pure white (#ffffff). Use a warm or cool off-white such as #f9f7f4 or oklch(98% 0.008 var(--hue)) to reduce halation and reading fatigue.

Target

• page background in long-form reading contexts
• article body background
• editorial / blog / marketing prose surfaces

Severity

high

Values

• • Forbidden: #ffffff
  • Forbidden Equivalent: rgb(255, 255, 255)
• • Forbidden: white
  • Forbidden Equivalent: oklch(100% 0 0)

Exceptions

• Cards / modals / tooltips where surface contrast against page background is the design intent.
• Dashboard data surfaces where pure white maximises legibility for tabular numerics.
• Print stylesheets — paper is the medium.

Approved Alternatives

• #f9f7f4 — warm paper-white (Atlantic / Readwise)
• oklch(98% 0.008 var(--hue)) — hue-aware off-white
• #fafaf7 — neutral off-white (Stripe long-form docs)
• #f5f5f4 — Tailwind stone-100

Enforcement

Stylelint custom rule rejecting background: #fff / background: white on selectors body, article, [role=main], .prose. Token review: --bg and --surface-page must not resolve to pure white in prose-context themes.

Rationale

Sustained reading against a 100%-white emissive surface causes pupillary constriction and accelerates eye fatigue. Editorial reading apps (Readwise Reader, Instapaper, Kindle) and premium publications (Atlantic, NYT Magazine) ship warm off-white paper-like surfaces (#f9f7f4–#fafaf7) for body backgrounds. Pure white remains acceptable for tight UI surfaces (cards, modals) where reading time is short.