Bring the entire product up to WCAG 2.2 AA. Front-end: keyboard reachability, focus-visible states, semantic landmarks, ARIA only where native semantics fall short, color contrast tokens audited in both themes, prefers-reduced-motion respect, captions and transcripts on demo videos, screen-reader pass on every primary flow (post create, comment, vote, status change, billing). Back-end: API errors return human-readable messages, error responses include WCAG-compliant status text for downstream renderers, server-rendered pages ship correct lang attributes, transactional emails use accessible HTML structure. Add an automated axe-core run to CI so regressions fail PRs.