Low color contrast
WCAG 1.4.3
Normal text needs a contrast ratio of at least 4.5:1 against its background. Large text (about 24px, or 19px bold) needs 3:1. Low contrast is the most common error on the web: WebAIM found it on 83.9% of home pages in 2026.
People with low vision, color blindness, or a phone screen in bright sunlight all struggle with pale gray text, light text on photos, and colored buttons with thin white labels.
The fix is almost always one color change. Your dashboard shows the exact failing color pairs and a nearby color that passes. Change it once in your theme's color settings, and every page that uses it gets fixed.