body {
            margin: 0;
            padding: 30px;
            background: #f5f5f5;
            font-family: Arial, sans-serif;
            text-align: center;
        }
        #viewer-wrapper {
            position: relative;
            width: 900px;
            max-width: 100%;
            margin: auto;
        }
        #viewer {
            width: 100%;
            height: 600px;
            border: 1px solid #ddd;
            background: #fff;
        }
        .thumbnail {
            width: 200px;
            height: 112px;
            cursor: pointer;
            margin: 10px;
            border: 1px solid #ccc;
            transition: border 0.2s;
        }
        .thumbnail:hover {
            border: 2px solid #f6611f;
        }
        #degree {
            margin-top: 10px;
            font-size: 18px;
            color: #333;
        }
        #thumbnails-wrapper {
            display: flex;
            justify-content: center;
            margin-top: 15px;
            gap: 20px;
        }