body{font-family:-apple-system,Segoe UI,Roboto,sans-serif;margin:0;background:#f4f6f8;color:#1a1a1a}header{background:#0f5fa8;color:#fff;padding:16px 24px}header h1{margin:0;font-size:1.3rem}main{max-width:960px;margin:0 auto;padding:20px}.register{background:#fff;border-radius:10px;padding:16px 20px;margin-bottom:16px}.register input{padding:6px 10px;margin-right:8px}.register-result code{display:block;word-break:break-all;margin:4px 0}.device-card{background:#fff;border-radius:10px;padding:16px 20px;margin-bottom:16px;box-shadow:0 1px 3px #0000001a}.device-header{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:8px}.device-id{font-weight:600;font-size:1.05rem}.badge{padding:3px 10px;border-radius:20px;font-size:.8rem;font-weight:600}.badge.open{background:#d7f5df;color:#157a3c}.badge.closed{background:#fbdada;color:#a3241f}.stats{display:flex;gap:24px;margin:12px 0;flex-wrap:wrap}.stat .label{font-size:.75rem;color:#666;text-transform:uppercase}.stat .value{font-size:1.2rem;font-weight:600}.buttons button{padding:8px 16px;border-radius:6px;border:none;font-weight:600;cursor:pointer;margin-right:8px}.btn-open{background:#157a3c;color:#fff}.btn-close{background:#a3241f;color:#fff}canvas{max-height:220px;margin-top:10px}.empty{text-align:center;color:#888;padding:40px}.last-seen{font-size:.75rem;color:#999}