Interactive UI elements must have a contrast ratio of at least 3:1 against their background in all states.
Insufficient button contrast:
This button has insufficient contrast ratio (1:1) against its background, making it difficult to distinguish as an interactive element:
Note: Possible to automatically test. This violation can be detected by querying all controls/interactive elements (e.g., buttons), programmatically retrieving their color attributes (e.g., from the CSS stylesheet), along with the background-color attributes of their background elements, and verifying that an appropriate contrast ratio exists between them.
If the color of an element or the background-color of the parent element cannot be determined, a human tester or AI is required to visually check the contrast ratio of an input element against its background.