What does this mean?
To comply with WCAG AA, the colour of text must sufficiently contrast with its background color, so that people with moderate visual impairments can read it.More help
The contrast ratio must be at least 4.5:1 for body text, and 3:1 for large text.
A much more demanding version of this check (1.4.6) exists for WCAG AAA. Ignoring an issue in this check will also ignore it in that check, and vice versa.
How close this website is to fixing this issue.