Elements must meet minimum color contrast ratio thresholds

Candidates are elements with a visible text node of their own, plus input, select and textarea fields, even empty ones, except a select without options and a field whose text-indent moves its text off the control. Skipped are textless inputs such as checkboxes, disabled or inert elements, labels of disabled controls, and text of only emoji or punctuation.

The check reads the computed text color and builds the background from the elements stacked behind the text, blending semi-transparent layers onto a white page. Text counts as large from a font-size of 18pt (24px), or 14pt (18.66px) when font-weight is 700 or more.

When the check cannot decide, the result is needs review, as with a background image or gradient, an image or video behind the text, another element on top, a large, absolutely positioned ::before or ::after with a background, or a single failing character. Validiscan’s scanner does not turn these into findings, so such text needs a person’s check.

Colors are read in the state the page loads in, with the light color scheme, at each scanned viewport. vs-hover-focus-contrast measures hover and focus states.