PrefersContrast [rule] v1.0.0

Designs must respond to prefers-contrast:more by increasing text and border contrast, and must use CSS system color keywords when prefers-contrast:forced is active to support Windows High Contrast Mode.

Meta

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

Severity

high

Implementation

• @media (prefers-contrast: more): increase text contrast to 7:1, thicken borders to at least 2px, remove low-opacity decorative elements
• @media (forced-colors: active): use system color keywords (ButtonText, Canvas, Highlight) — do not fight the OS-provided color scheme
• Do not use box-shadow as the sole border indicator — shadows are invisible in forced-colors mode
• Focus indicators must use outline, not box-shadow, in forced-colors mode

Css Skeleton

    @media (prefers-contrast: more) {
      :root {
        --color-text: oklch(10% 0 0);    /* near-black */
        --color-border: oklch(20% 0 0);  /* heavy border */
      }
      .btn { border: 2px solid currentColor; }
    }
    @media (forced-colors: active) {
      .btn { forced-color-adjust: auto; }
      /* Do not override: let OS colors apply */
    }
  

PrefersContrast [rule] v1.0.0

Designs must respond to prefers-contrast:more by increasing text and border contrast, and must use CSS system color keywords when prefers-contrast:forced is active to support Windows High Contrast Mode.

Meta

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

Severity

high

Implementation

• @media (prefers-contrast: more): increase text contrast to 7:1, thicken borders to at least 2px, remove low-opacity decorative elements
• @media (forced-colors: active): use system color keywords (ButtonText, Canvas, Highlight) — do not fight the OS-provided color scheme
• Do not use box-shadow as the sole border indicator — shadows are invisible in forced-colors mode
• Focus indicators must use outline, not box-shadow, in forced-colors mode

Css Skeleton

    @media (prefers-contrast: more) {
      :root {
        --color-text: oklch(10% 0 0);    /* near-black */
        --color-border: oklch(20% 0 0);  /* heavy border */
      }
      .btn { border: 2px solid currentColor; }
    }
    @media (forced-colors: active) {
      .btn { forced-color-adjust: auto; }
      /* Do not override: let OS colors apply */
    }
  

Relations

related: [@community/rule-color-contrast, @community/constraint-accessibility-aa-minimum, @community/check-contrast-aa]

Meta

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

Severity

high

Implementation

• @media (prefers-contrast: more): increase text contrast to 7:1, thicken borders to at least 2px, remove low-opacity decorative elements
• @media (forced-colors: active): use system color keywords (ButtonText, Canvas, Highlight) — do not fight the OS-provided color scheme
• Do not use box-shadow as the sole border indicator — shadows are invisible in forced-colors mode
• Focus indicators must use outline, not box-shadow, in forced-colors mode

Css Skeleton

    @media (prefers-contrast: more) {
      :root {
        --color-text: oklch(10% 0 0);    /* near-black */
        --color-border: oklch(20% 0 0);  /* heavy border */
      }
      .btn { border: 2px solid currentColor; }
    }
    @media (forced-colors: active) {
      .btn { forced-color-adjust: auto; }
      /* Do not override: let OS colors apply */
    }