Display an overarching 'theme accessibility' notice which directs users to any blocks that may have colour contrast issues

[thatisrich]

What problem does this address?

The colour contrast notification displays a notice within a block / element when its selected colours do not meet the AA contrast ratio, however this notice is only visible when viewing that block / element.

Displaying a Themer-wide notification that directs users to any colours that may need updating could bring accessibility issues to the surface, making them easier to address.

What is your proposed solution?

Using a variation of the proposed custom colour contrast component, a notice could be displayed within the layout grid like in this quick mockup.

As outlined here, this example mockup will need refining to ensure it fits the use case correctly.