:root { color-scheme: dark; --bg: #000; --text: #e8f1fb; --muted: #8ea3bd; --accent: #3fbf7f; }
* { box-sizing: border-box; }
html, body { height: 100%; }
body { margin: 0; display: grid; place-items: center; padding: 16px; background: var(--bg); color: var(--text);
       font: 15px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
main { display: grid; justify-items: center; gap: 12px; text-align: center; }
.mark { width: 48px; height: 48px; border-radius: 12px; background: var(--accent); color: #04140b; font-weight: 800;
        font-size: 24px; display: grid; place-items: center; animation: pulse 1.4s ease-in-out infinite; }
@keyframes pulse { 50% { opacity: .35; } }
#status { margin: 0; color: var(--muted); }