The Web Accessibility Guide

A current handbook that explains every WCAG 2.2 success criterion with illustrated examples of what passes and what fails. The clearest reference here if you have to meet an accessibility standard.

Digital Policy Office

An open textbook on building accessible interactivity: testing with a screen reader, using WAI-ARIA landmarks and live regions, and creating accessible progress bars, tooltips, and suggestion boxes. Covers graceful degradation and progressive enhancement.

Greg Gay and Igor Karasyov

More than two hundred design guidelines, each rated for the strength of the research behind it, covering navigation, page layout, links, text, forms, and search. Still one of the most cited usability references in the field.

US Department of Health and Human Services

A guide to writing and designing sites that work for readers with limited literacy, built on testing with real participants. The plain language and layout advice transfers to any audience you cannot afford to lose.

Office of Disease Prevention and Health Promotion