body {
            background-color: #2f2f2f;
            color: #ffffff;
            font-family: Arial, Helvetica, sans-serif;
            margin: 0;
            padding: 0;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
        }
        .dvr-container {
            width: 960px;
            height: 600px;
            background-color: #1a1a1a;
            border: 2px solid #444;
            box-shadow: 0 0 20px rgba(0,0,0,0.8);
            display: flex;
            flex-direction: column;
        }
        .dvr-header {
            background-color: #333;
            padding: 10px 20px;
            border-bottom: 1px solid #444;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 14px;
            font-weight: bold;
            color: #aaa;
        }
        .dvr-main {
            flex: 1;
            display: flex;
            background-color: #111;
        }
        .dvr-sidebar {
            width: 200px;
            background-color: #222;
            border-right: 1px solid #333;
            padding: 15px;
            box-sizing: border-box;
        }
        .cam-list {
            list-style: none;
            padding: 0;
            margin: 0;
        }
        .cam-item {
            padding: 8px 10px;
            margin-bottom: 5px;
            background-color: #2a2a2a;
            border: 1px solid #3a3a3a;
            font-size: 12px;
            color: #ccc;
            cursor: pointer;
        }
        .cam-item:hover {
            background-color: #3a3a3a;
        }
        .dvr-viewport {
            flex: 1;
            background-color: #000;
            position: relative;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .error-overlay {
            text-align: center;
            max-width: 450px;
            padding: 30px;
            background: rgba(20, 20, 20, 0.9);
            border: 1px solid #cc0000;
            border-radius: 4px;
        }
        .error-icon {
            font-size: 48px;
            color: #cc0000;
            margin-bottom: 15px;
        }
        .error-title {
            font-size: 16px;
            font-weight: bold;
            color: #ff3333;
            margin-bottom: 10px;
        }
        .error-text {
            font-size: 13px;
            color: #bbb;
            line-height: 1.5;
            margin-bottom: 20px;
        }
        .btn-download {
            display: inline-block;
            background-color: #444;
            color: #fff;
            padding: 8px 20px;
            text-decoration: none;
            font-size: 12px;
            border: 1px solid #555;
            border-radius: 3px;
            font-weight: bold;
            cursor: not-allowed;
        }
        .dvr-footer {
            background-color: #222;
            padding: 5px 20px;
            font-size: 11px;
            color: #666;
            text-align: right;
            border-top: 1px solid #333;
        }