What this means
People need to see where to enter an answer or select an option. A border used to identify a field needs at least 3:1 contrast against the adjacent background. Checkbox and radio-button outlines count too.
Passing examples
- An empty checkbox has an outline measured at 4:1 against the form background.
- A text field's border meets 3:1 against the colors directly inside and outside it.
- In dark mode, light field outlines remain clearly visible against the dark background.
Failing examples
- A white field has a faint gray outline measuring only 1.5:1 on white.
- Unchecked boxes blend into the page, though their checked marks are clear.
- Dark borders disappear when the form switches to a dark background.
A border is not required if another clear visual treatment identifies the field. Where a border is the identifying feature, it must meet the contrast requirement.