body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background: #1a1a1a; color: #efefef; padding: 40px; }
.container { max-width: 600px; margin: 0 auto; }
.device-list { background: #2a2a2a; border-radius: 8px; overflow: hidden; margin-top: 20px; }
.device-item { padding: 12px; border-bottom: 1px solid #3d3d3d; display: flex; align-items: center; gap: 10px; }
.group-header { background: #3d3d3d; padding: 5px 12px; font-size: 0.8em; text-transform: uppercase; color: #aaa; }
.actions { display: flex; gap: 10px; margin-bottom: 20px; }
button { padding: 10px 20px; border: none; border-radius: 4px; cursor: pointer; background: #007bff; color: white; }
button:disabled { background: #444; cursor: not-allowed; }
.qr-card { background: white; color: black; padding: 15px; border-radius: 8px; text-align: center; margin-top: 10px; }
.qr-card img { width: 200px; }