In order to know how to interact with a control or form field you get visual cues that tell you what it is. To help our users with low vision also identify these interactive elements we need the pieces that are needed for identification to have high enough contrast.
- Visual information that is needed to identify a user interface component, such as buttons and form fields, needs to have a contrast ratio of at least 3.00:1 against adjacent color(s) (measured out to 2 decimal places). This applies in all states (ex. selected, focused, pressed, and checked).
- Inactive components are exempt from this standard.
- When the appearance of the component is determined by the user agent and not modified it is exempt from this standard.
In the example below the bottom border is needed to identify the text input so that indicator must meet a 3.00:1 contrast ratio. The light gray background is not needed to identify the component so it does not have requirements.
In this second example a complete border is used so the entire border must meet a 3.00:1 contrast ratio.
In this example the input is differentiated only by a background color so the input must have a 3.00:1 contrast ratio to the adjacent background.