WCAG (Web Content Accessibility Guidelines) 2.0 Level AA standards ensure that content is accessible by everyone, regardless of any disability or user device.
To ensure text remains compliant with WCAG standards, use only these permitted color combinations. These options have a minimum contrast ratio of at least 4.5:1.
More Information in the WCAG 2.0 Guidelines
This color contrast tool is a useful resource for testing the compliance of any color combination.