Acessibility.Works
A website should be Perceivable, Operable, Understandable, and Robust.
Web Content Accessibility Guidleines (WCAG)
aka W3C:
Visual contrast ratios - in both size and color - are important.
usability.gov
Don't use color as the sole navigation tool, and always provide text
(captions or descriptions) that can stand in for any given picture.