NHM Paleontology — Museum Exhibition — Référence de design web et prompt

# NHM — Natural History Museum Paleontology Landing

## Overview

Build a single-page, monochrome landing page for the Natural History Museum's paleontology collection. The page is one continuous scroll with three sections — a full-viewport hero with a delayed background video and a geometric "NHM" logotype, an "Explore Our World" intro section, and a dark "Ancient Collection" chapter browser featuring an SVG-filter sand/dissolve image transition. The entire page is a single `App.tsx` component plus a `SandTransitionImage` helper and a `LeafIcon` helper in the same file.

## Tech Stack

- **Framework:** React 19 (`react`, `react-dom` `^19.0.1`) with `StrictMode`
- **Build tool:** Vite 6 (`vite` `^6.2.3`, `@vitejs/plugin-react` `^5.0.4`)
- **Language:** TypeScript (`typescript` `~5.8.2`, `@types/react` `^19.0.10`, `@types/react-dom` `^19.0.4`)
- **Styling:** Tailwind CSS 4 (`tailwindcss` `^4.1.14`, `@tailwindcss/vite` `^4.1.14`) — CSS-first config via `@theme`