WCAG (Web Content Accessibility Guidelines) defines accessibility standards.
Levels:
- Level A: Minimum accessibility
- Level AA: Standard target for most sites
- Level AAA: Highest accessibility
Four principles (POUR):
Perceivable: Users can perceive content
Operable: Users can navigate and interact
Understandable: Content and UI are understandable
Robust: Works with assistive technologies
Interview tip: Know WCAG AA is the typical target. Reference specific guidelines when relevant.