A review blocks on evidence, not taste. In accessibility the evidence is a WCAG 2.2 Level A or AA criterion by number, or a concrete task an assistive-technology user cannot complete. Everything else — AAA, APG conventions, one <h1> per page, no skipped heading levels, 44px touch targets — is a recommendation and never the top severity in a review-format table.

The numbers

Criterion	Rule
1.4.3 Contrast	Text 4.5:1; large text (≥ 24px, or ≥ 18.67px bold) 3:1
1.4.11 Non-text contrast	Component boundaries, states and meaningful graphics 3:1 — includes input borders and custom focus rings against every adjacent colour
1.4.1 Use of colour	Status never by colour alone: add an icon, text or underline
2.5.8 Target size	24×24 CSS px, or a smaller target spaced so a 24px circle centred on it touches no other target (links inside a sentence are exempt)
2.5.7 Dragging	Every drag has a single-pointer alternative — buttons or a menu that reach the same result
2.4.7 / 2.4.11 Focus	A visible indicator, and the focused element never fully hidden behind a sticky header, footer or banner
1.4.4 Resize text	Everything survives 200% text
1.4.10 Reflow	Works at 320px wide (400% zoom on 1280px) with vertical scroll only; tables, maps and code scroll in their own box
2.2.2 Pause, stop, hide	Anything that moves, blinks or updates itself for more than 5 s has a visible pause
1.4.2 Audio control	Nothing autoplays with sound

Inactive controls and logos are exempt from contrast. Measuring a pair is a colour job (contrast-and-color-scheme, color-scales-oklch): measure the foreground against what it actually renders on, report the pair, the value and the threshold missed, and leave the colours alone unless asked.

The fixes the numbers imply

Targets — keep the visual small and grow the hit area with a pseudo-element; hit areas never overlap; decorative layers get pointer-events: none so a glow never swallows the click beneath it. Aim for 44px touch and 40px desktop where density allows (touch-and-focus), but keep an established, usable dense tool dense.
Focus under sticky chrome — scroll-padding-block-start on the scroller equal to the header's height; -block-end for a sticky footer or cookie bar (growth-and-overflow).
Zoom — never maximum-scale=1 or user-scalable=no; the iOS input-zoom fix is a 16px input, not a locked viewport (forms-behavior). Text boxes take min-height, never height. Write media queries in rem so a larger browser font size reaches the narrow layout.
Forced colours — Windows High Contrast drops every box-shadow. A shadow ring keeps border: 1px solid transparent under it so an edge still draws; never forced-color-adjust: none without checking the control stays visible.
Timed UI — auto-dismiss only low-stakes confirmations. A toast carrying an action, an error or something the user may need stays until dismissed; one that must time out gets ≥ 5 s and pauses while hovered or focused. An undo link that vanishes on a timer is data loss on a schedule.

Gotcha

This graph reaches for APCA when designing contrast (contrast-and-color-scheme). A finding still cites the WCAG 2 ratio, because that is the criterion a product is held to. Pass both; report the one with a number on it. The split is settled in interfaces-reconciliation.

Sources

Jakub Krehel, interfaces skills (MIT, github.com/jakubkrehel/skills, HEAD 592aedc, read 2026-10-25): skills/better-accessibility/SKILL.md (Criteria, not conventions, Minimum hit area, Pair color with a second cue, Survive zoom and text resize), hit-areas.md, motion-and-zoom.md, focus-and-keyboard.md; skills/better-ui/SKILL.md (the forced-colors border).
W3C, Web Content Accessibility Guidelines 2.2 — success criteria as numbered above.
Related: accessibility-baseline, keyboard-patterns, screen-reader-announcements, prefers-reduced-motion.