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Aristeia
Accessibility in Motion & 3DPenelopepattern

Reduced Motion Contract

One honest global switch — system preference plus user override — that every animation layer already reads.

Built here · no external address

Penelope: Long-running fidelity. Maintained excellence over years.

Why it matters

Reduced motion that guts the page is pity. Reduced motion that freezes to a still, beautiful frame is care.

Key techniques

  • prefers-reduced-motion consulted at play time and in CSS.
  • data-reduced-motion on html for a user override.
  • Lenis, Kinetic, Aura, Cursor, Armory all honour the same contract.

What to steal

The transferable part.

Still, not absent. Keep composition; remove travel.

What not to copy

Context-specific or costly.

Do not maintain a second design system for reduced motion.

Inclusion rationale

Opens Asclepius with the contract the rest of the building already claims.

Technical register

Performance

Skipping RAF work is a performance win as well as an a11y win.

Mobile

OS toggles are common; test both.

Accessibility

This entry is the Asclepius seed — motion accessibility as structure.

Study next

Related entries

HermesWeighted EasingA staggered reveal with its timeline exposed as a scrubbable value, so stagger stops being a feeling and becomes a number.AthenaFocus-Visible ContractOne ring treatment for the whole app — never removed, never replaced by colour alone, always :focus-visible.HephaestusThe Instanced ForgeFour thousand ingots drawn in a single call, with the draw-call figure published next to the frame time so the cost of the scene is stated rather than implied.HephaestusThe Struck IngotAn object with no vertices — a signed distance field marched per pixel, with the step budget exposed so the exact moment quality is bought back is visible.