The 4 Core Principles of WCAG (POUR)

The Web Content Accessibility Guidelines (WCAG) 2.1 and 2.2 are organized around four fundamental principles, known as the POUR framework:

1. Perceivable: Information and user interface components must be presentable to users in ways they can perceive (e.g., text alternatives for icons, sufficient color contrast, captions for video).
2. Operable: Interface components and navigation must be operable (e.g., all functionality accessible via keyboard, no trapped focus, ample time to complete tasks).
3. Understandable: Information and operation of the UI must be clear and predictable (e.g., clear error messages, consistent navigation patterns, readable typography).
4. Robust: Content must be robust enough to be interpreted reliably by a wide variety of user agents, including modern assistive technologies like screen readers.