Use of color should not interfere with the ability to view content on a page.
When color is used to define states or actions on a web page, the lack of ability to see or process those colors can lead to missed content and navigation.
Account for contrast and color deficiency in all designs.
Use an online tool to check a page in black and white or in color deficiency mode to understand any problematic color choices.
Use more than one type of sensory characteristic to show meaning.
For more information, visit the WCAG links for this topic.