Vaultra Hero — Référence de design web et prompt

# Prompt: Vaultra crypto finance hero

Build a single-file, one-screen **landing hero for a fictional crypto finance platform, Vaultra**. Use plain HTML, CSS and vanilla JS, with no framework and no build step. The look is a black night with a huge dotted particle globe rising from the bottom. Its rim glows red, blue and magenta, and it **slowly spins**. Thin straight light lines and small glass coin chips cross the dark sky, and a large gradient headline sits on top.

## Media

- **Globe still:** `https://d2ol7oe51mr4n9.cloudfront.net/user_38xzZboKViGWJOttwIXH07lWA1P/f1631235-0a76-464d-8f1d-2c4b48a997d5.jpg` (1672×941). The dotted particle globe with latitude rings and coloured rim glows, plus the thin diagonal lines and nodes.
- **Globe video:** `https://d2ol7oe51mr4n9.cloudfront.net/user_38xzZboKViGWJOttwIXH07lWA1P/e71aea27-a808-4ae3-8231-a469d49285d4.mp4` (1280×720, 4s, muted, loops). The same globe rotating steadily left to right, with its particle rings sliding and its rim glows shimmering. The camera is still and the lines don't move.
  - The last second crossfades into the first, so it loops with no jump and never plays in reverse.
  - It sits over the still with identical geometry and fades in once its first frame is ready.
- **Masks:** both layers stretch to a plate that covers the hero. They're feathered at the sides on ultra-wide screens and at the top on phones.
- **Rule:** nothing in the scene is drawn or animated in code.