WCAG 1.4.1 — Color Is the Only Visual Means of Conveying Information

Your website uses color as the only way to communicate certain information — for example, marking required form fields only in red, showing calendar availability only through green and gray colors, or distinguishing chart categories only by color. Approximately 8% of men have some form of color blindness and cannot reliably distinguish certain color combinations. Information conveyed only through color is inaccessible to these users and must also be communicated through text, pattern, shape, or another non-color means.