Robot Jellyfish — Référence de design web et prompt

# Robot Jellyfish — Medusa JF-4 3D Field Simulator Hero (exact recreation prompt)

Build a single-file, full-viewport interactive page called **Medusa JF-4**. It is a live three.js field simulator of a robotic jellyfish that you can take apart piece by piece. A huge procedural 3D machine floats in the centre of a pale aqua-white instrument dashboard, and a 25-second looping tour opens each assembly in turn while every gauge on the page reacts.

There are no images, no video and no model files. Every petal, gear, link and rivet is three.js code. Plain HTML, CSS and one vanilla ES module in one file. The only external resources are the two Google Fonts and three.js 0.170.0 from jsDelivr. Reproduce every value, string and timing below exactly. The CSS, markup and script are given verbatim, so copy them without changes.

Four rules define it:
1. **Everything is a function of the playhead.** The pose of the whole machine, the camera and the HUD derive from one time value `t` in 0–25 s, so scrubbing the timeline works perfectly in both directions.
2. **It is one continuous machine.** Nothing crossfades. Parts hinge, unscrew, telescope and fly apart mechanically.
3. **Arms are chains.** Each of the 8 arms is 28 links, posed every frame by walking along the chain and accumulating a bend per link. There are 224 links.
4. **The page stays light and technical.** Pale aqua-white ground, deep teal ink, one coral accent, tiny spaced monospace labels, thin rings behind the model.