Halcyon

# BUILD SPEC — "HALCYON" · Space Travel Hero (single-screen, video background)

Build exactly this. Every number is measured, not a suggestion. If a value isn't listed, derive it from the ones that are — never invent a visual idea.

## 1. CONCEPT
**Halcyon**, private spaceflight operator. One single screen, exactly `100dvh`, **no scroll, nothing below the fold**. Full-bleed slow-motion video of a sunlit field behind a pale-blue atmospheric gradient; over it a thin uppercase nav, a two-line serif headline that assembles word by word out of blur, a lede, two buttons, a right-hand data column with a drawn hairline,…