1.4.3 Contrast (Minimum)

Introduction

This document provides information about these Acquia Web Governance automated accessibility checks:

• Link text fails minimum contrast requirements on hover
  Link text must contrast with the background in all states, including the hover state. 
• Link text fails minimum contrast requirements when active
  Link text must contrast with the background in all states, including the active state. 
• Link text fails minimum contrast requirements when visited
  Link text must contrast with the background in all states, including the visited state. 

What

Low contrast makes links difficult to read. As a result, users with low vision or color blindness might not find or use these links. Sufficient contrast helps all users read your content, including persons in bright light or with low-quality screens. The color of link text in all user-induced states such as hover, focus, active, and visited must have sufficient contrast with its background. The required contrast ratios are:

• At least 4.5:1 for standard-sized text.
• At least 3:1 for large-scale text (24px or 18.67px bold).

This ensures that link text remains legible and accessible under all conditions.

Why

This section provides information about why this check is important and provides some examples.

Why is this important?

Sufficient contrast provides the following:

• Maintains readability in all interactions: Users can read link text regardless of its state.
• Ensures accessibility for visually impaired users: Users can easily distinguish high contrast link text.
• Prevents usability issues: Links that change color on hover or focus remain visible.

Examples

This section provides some pass and fail examples.

Pass examples

• Sufficient contrast for all states

  copy

  a {
    color: #0055cc; /* Contrast ratio: 7.1:1 on white */
  }
  a:hover,
  a:focus {
    color: #003399; /* Contrast ratio: 5.2:1 on white */
  }

  • Why this works:
    • The default link color (#0055cc) has sufficient contrast against the white background (7.1:1).
    • The hover/focus color (#003399) maintains a contrast ratio above 4.5:1.

• Large-scale text requires 3:1 contrast

  copy

  .large-link {
    font-size: 24px;
    color: #666666; /* Contrast ratio: 4.2:1 */
  }
  .large-link:hover {
    color: #555555; /* Contrast ratio: 3.5:1 */
  }

  • Why this works:
    • The text is 24px or larger.
    • The colors maintain the required contrast.

Fail examples

• Insufficient contrast in default state

  copy

  a { 
    color: #888888; /* Contrast ratio: 2.5:1 on white */ 
  } 
  

  • Issue:
    • The contrast is below 4.5:1, which fails to meet the criteria.

  • Fix:

    copy

    a {
      color: #0055cc; /* Contrast ratio: 7.1:1 */
    }

• Hover/focus state fails contrast requirement

  copy

  a {
    color: #0055cc; /* Good contrast */
  }
  a:hover {
    color: #999999; /* Contrast ratio: 2.8:1 */
  }

  • Issue:
    • The hover color (#999999) is below 4.5:1, which fails to meet the criteria.

  • Fix:

    copy

    a:hover {
      color: #003399; /* Contrast ratio: 5.2:1 */
    }

• Large text fails contrast minimum (requires 3:1)

  copy

  .large-link {
    font-size: 24px;
    color: #aaaaaa; /* Contrast ratio: 2.7:1 */
  }

  • Issue:
    • The contrast is below the required 3:1 for large text.

  • Fix:

    copy

    .large-link {
      color: #666666; /* Contrast ratio: 4.2:1 */
    }
    How

How

This section provides instructions on how to review and fix the issue.

How to review it

1. Identify all user-induced states of links:
   • Default
   • Hover
   • Focus
   • Active
   • Visited
2. Use a contrast checker like the Acquia Color Contrast Checker to verify that each instance meets the requirements:
   • 4.5:1 for normal text
   • 3:1 for large-scale text
3. Ensure that all interactions maintain readability and do not cause color contrast failures.

How to fix it

• Use sufficiently contrasting colors

  copy

  a {
    color: #004488; /* Contrast 7.1:1 */
  }
  a:hover {
    color: #002266; /* Contrast 5.8:1 */
  }

• Use contrast detection tools such as:

  • Acquia Color Contrast Checker
  • Google Chrome DevTools on the
    Accessibility
    tab

Additional resources

Acquia Color Contrast Checker

WCAG criteria

1.4.3 Contrast (Minimum)

Link text fails minimum contrast requirements in active states