:root{--bg: #0f172a;--text: #e2e8f0;--muted: #94a3b8;color-scheme:dark}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text);min-height:100vh;display:flex;align-items:center;justify-content:center}.container{text-align:center;padding:2rem}header h1{margin:0;font-size:2rem}.subtitle{color:var(--muted);margin-top:.5rem}