Halora — Référence de design web et prompt

# Prompt: Halora — smart ring hero, Sage Studio

Build a single-file, one-screen **landing hero for a wellness smart ring**, **Halora**. Use plain HTML, CSS and vanilla JS, with no framework and no build step. The look is a calm, sunlit editorial product photo: a real hand rises from the bottom edge against a pale sage wall, a rose-gold ring with a black inner band floats between its fingers, olive-leaf shadows fall across the right side, and a thin clear glass circle arcs behind the hand. Copy sits on the left and three frosted glass metric cards stand on the right.

## Scale

- **Units:** every stage measurement is a reference pixel of a 2048×1152 artboard, multiplied by `--s = min(100vw/2048, 100vh/1152)`, with a floor of 0.55px on desktop.
- **Photo:** fitted to the viewport height and anchored to the bottom, so the arm always leaves the frame at the bottom edge. Up to about 2:1 it behaves like cover; on ultra-wide screens it stops growing and its sides fade into the sage backdrop.
- **Fill:** the hero always fills the viewport, with no letterbox bands.

## Type and colour