• Success Criterion 1.4.3
  • Conformance level AA

Dark Mode Theme Shipped With Untested Contrast Combinations

1.4.3 — Contrast (Minimum)

Scenario

Setting

A photo-sharing app's upload screen

What’s wrong

Dark-mode theme shipped with untested combos below ratio.

Example 

/* dark theme */
.upload-caption { color: #4b5563; background: #111827; }
<!-- roughly 1.9:1, far below the 4.5:1 minimum -->

Why it matters

A photographer captioning a photo at night in dark mode can barely see the text they're typing into the caption field.

How to test

Toggle dark mode and re-measure every text/background combination: colors that pass in light mode often fail when inverted.

How to fix

Test every dark-theme color pairing separately from light mode; this swap raises contrast to roughly 11.6:1.

.upload-caption { color: #d1d5db; background: #111827; }

Outcome

The photographer writes a caption at night without straining to see what they're typing.

Who is affected

Low-vision users, who chose dark mode expecting comfortable contrast, not a theme that was never checked against WCAG.

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