Wikipedia:Manual of Style/Accessibility/CSS colors for text on white

Recommended
For text against a white background, the following CSS colors meet the minimum contrast ratio (4.5:1) specified by Web Content Accessibility Guidelines (WCAG) 2.0 Level AA.

Not recommended
For text against a white background, the following CSS colors do not meet the minimum contrast ratio (4.5:1) specified by Web Content Accessibility Guidelines (WCAG) 2.0 Level AA.