Hover, focus, and active on buttons and links
(and when a Sufficent Technique is insufficient)
These paragraphs contain and some links that have the default styling removed so that they appear as plain text within the paragraphs.
For keyboad and mouse users, the button and links can be discovered through hovering or tabbing to those elements. On a mobile device without a keyboard, what are the consequences?
WCAG 2.1 has a Sufficient Technique, G183, for the 1.4.1 Use of Color Success Criterion that says link text that contrasts from other text by 3:1, while still being sufficiently contrasty from its page background, provides a sufficient affordance to meet Use of Color requirements, when paired with a focus or hover effect — that is, that simple text contrast provides sufficient visual difference to discern a link from plain text, so long as another visual cue appears when the link is hovered or focused.
Some of the links on this page meet those requirements, and other links have no non-hovered/non-focused styling at all, in order to mimic what it might be like to discern links styled via color contrast alone, if you had diminished color perception.
We can readily see that the G183 technique creates a (acceptable??) barrier for Use of Color. But what if you are accessing this page on a mobile device? Now G183 is a blocker, not just a suboptimal technique. How would you detect the focus or hover affordance if you can't hover or focus? Must we just accept the G183 technique as adequate? WCAG says Sufficient Techiques are always “sufficienct,” right?
Wrong! All is not lost. WCAG provides for the non-applicability of any Sufficient Technique by requiring that Sufficient Techniques also be “accessibility supported.” Since the technique is not accessibility supported on mobile devices (unless you are using a keyboard or have a mouse attached), if you have determined that the consituency of users for your web site may be using a mobile device, such as a phone or a tablet, then WCAG says G183 can be discounted as sufficient for conformance to Use of Color. Hurray! We can void this lousy technique!