Web Content Accessibility Guidelines (WCAG)
The Web Content Accessibility Guidelines (WCAG) are a highly detailed set of technical rules published by the WAI that explain exactly how to make web content accessible to people with disabilities. The guidelines are organized into four core principles—content must be Perceivable, Operable, Understandable, and Robust (POUR)—and are graded on three levels of strictness: A (Minimum), AA (Standard), and AAA (Exceptional).