:root { color-scheme: dark; font-family: system-ui, sans-serif; }
* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; margin: 0; overflow: hidden; color: #fff; background: #000; }
main { position: fixed; inset: 0; }
video { display: block; width: 100%; height: 100%; object-fit: cover; object-position: center; }