Semantic HTML
Using HTML elements for their meaning — headings, lists, buttons, labels — rather than generic divs and spans.
Semantic elements expose structure and behavior to assistive technology for free. A real <button> is focusable, clickable, and announced as a button; a styled <div> is none of those without extra work.
It’s the foundation of WCAG 1.3.1 and the reason “use the right element” beats piling on ARIA.