# Motion runtime The canonical inline JavaScript that powers every cinematic prototype. This file is the **single source of truth** for the runtime; `prototype --cinematic` embeds it verbatim and customizes only the register-specific configuration constants at the top. ## Contract The runtime is responsible for: 1. Booting **Lenis** smooth scroll (or skipping it under reduced motion). 2. Tracking the **nav scrolled state** (toggles `.scrolled` on the sticky/fixed nav element when scroll passes a threshold). 3. Registering every `[data-anim]` and `[data-tile-anim]` element for **scroll-progress reveal** with per-band stagger. 4. Driving the **rAF loop** that reads `lenis.scroll` once per frame and applies parallax + scroll-entrance transforms. 5. Wiring **IntersectionObservers** for `[data-countup]`, `[data-flip]`, and `[data-fill]` (one-shot reveals). 6. Splitting `[data-split]` element text into per-letter spans on measure. 7. Re-measuring on `resize` and on `window.load`. 8. **Reduced-motion** detection at boot — when on, neutralizes everything and forces final states. ## The canonical script This block ships in every cinematic prototype, after the Lenis `