A website should support different ways of use.
Automated tools find some issues. Keyboard use, screen readers, zoom and content clarity also need manual review.
Structure and meaning
Headings, regions, links and controls receive semantics that match their actual purpose.
Focus and keyboard
Every action must work without a mouse, with visible focus and no traps inside menus, dialogs or forms.
Contrast and motion
Text and controls receive sufficient contrast while reduced motion removes movement that is not needed for comprehension.