Color is not used as the only visual means of conveying information
Text has a contrast ratio of at least 4.5:1
Content can be presented with no loss to info or functionality and without two-dimensional scroll
UI and graphical objects have a color contrast ratio of at least 3:1
Content on hover of focus is dismissible.
Keyboard accessible - All content is operable through a keyboard interface
Keyboard focus can be moved away from a component if it can be received
Keyboard character shortcuts use a modifier key and/or can be turned off/remapped
Bypass blocks - a mechanism is available to bypass blocks of content that are repeated.
Focus order preserves meaning and operability
Keyboard focus indicator is visible
Focus indicators are at least 2px thick and have a contrast of 3:1.
UI components visual labels matches their name labels
The size of the target for pointer inputs is at least 44 by 44 CSS pixels
A mechanism is available for identifying specific pronunciation of words
On input the 'context' for the user isn't changed without warning them.
Labels or instructions are provided when content requires user input.
Submitted information is either: reversible, checked for errors or asked for review / confirmation.
HTML can be parsed correctly, no duplicate attributes, unique IDs
UI components name and role can be programmatically determined.
Notify users about status changes that don't take focus