ref-sp-ux-accessibilitylisted

# UX Accessibility ## Purpose Hold the normative floor. Every accessibility number this repo states lives here, versioned and sourced, so that no other skill invents a threshold and no two skills disagree. ## When to use this skill - Asked whether something "is accessible", or asked to audit a page, component, or design against WCAG. - Checking a specific value: contrast ratio, tap target size, font size, focus indicator, line height, reflow width. - Adding or reviewing ARIA, roles, labels, or alt text. - Choosing between a `<div>` and a real element, adding landmarks, or fixing heading structure — including when the question arrives as "does semantic HTML help SEO or AI?" - Keyboard navigation, focus order, focus visibility, or skip links. - Reduced motion, autoplay, or interaction-triggered animation. - Someone proposes APCA, an accessibility overlay, or an automated score as proof of conformance. **Route elsewhere when:** the question is how something should *look* — spacing rhythm, palette construction, type scale, hierarchy, readability of prose — that is `.agents/skills/ref-sp-ux-design/SKILL.md`. **The ownership rule, stated so it can be checked:** every WCAG threshold value in this repo lives here, in `./references/thresholds.md`. `ref-sp-ux-design` cites criterion numbers and never their values, with one recorded exception (the 80-character measure cap, because it is the object of a correction there). If a threshold value appears in a third place, this sk