* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Noto Sans SC', sans-serif;
        }
        
        body {
            display: flex;
            background: linear-gradient(135deg, #1e3c72, #2a5298);
            color: #333;
            min-height: 100vh;
            overflow: hidden;
        }
        
        .container {
            display: flex;
            flex-direction: column;
            width: 100%;
            height: 100vh;
            padding: 20px;
            gap: 20px;
        }
        
        header {
            background: rgba(255, 255, 255, 0.9);
            border-radius: 12px;
            padding: 15px 20px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15);
            text-align: center;
        }
        
        h1 {
            color: #2a5298;
            font-size: 1.8rem;
            margin-bottom: 10px;
        }
        
        .subtitle {
            color: #555;
            font-size: 1rem;
            max-width: 800px;
            margin: 0 auto;
            line-height: 1.5;
        }
        
        .main-content {
            display: flex;
            flex: 1;
            gap: 20px;
            min-height: 0;
        }
        
        .viewer-container {
            flex: 1;
            background: rgba(255, 255, 255, 0.85);
            border-radius: 12px;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
            overflow: hidden;
            position: relative;
        }
        
        #model-viewer {
            width: 100%;
            height: 100%;
            display: block;
        }
        
        .controls {
            width: 350px;
            background: rgba(255, 255, 255, 0.9);
            border-radius: 12px;
            padding: 25px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.12);
            display: flex;
            flex-direction: column;
            gap: 20px;
            overflow-y: auto;
        }
        
        .card {
            background: white;
            border-radius: 10px;
            padding: 20px;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
            transition: all 0.3s ease;
        }
        
        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.12);
        }
        
        h2 {
            color: #2a5298;
            font-size: 1.3rem;
            margin-bottom: 15px;
            padding-bottom: 10px;
            border-bottom: 2px solid #eaeaea;
        }
        
        .control-group {
            margin-bottom: 20px;
        }
        
        label {
            display: block;
            font-weight: 500;
            margin-bottom: 8px;
            color: #444;
        }
        
        input[type="range"] {
            width: 100%;
            margin-top: 8px;
            height: 6px;
            background: #e0e0e0;
            outline: none;
            border-radius: 3px;
            -webkit-appearance: none;
        }
        
        input[type="range"]::-webkit-slider-thumb {
            -webkit-appearance: none;
            width: 18px;
            height: 18px;
            border-radius: 50%;
            background: #2a5298;
            cursor: pointer;
            border: 2px solid white;
            box-shadow: 0 0 3px rgba(0,0,0,0.2);
        }

        footer {
            background: linear-gradient(to right, #2c3e50, #1a2530);
            color: #ecf0f1;
            text-align: center;
            padding: 20px;
            margin-top: 25px;
            border-radius: 0 0 10px 10px;
        }
        
        .btn-group {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }
        
        .btn {
            flex: 1;
            min-width: 120px;
            padding: 12px 15px;
            border: none;
            border-radius: 6px;
            background: linear-gradient(to right, #3a7bd5, #3a6073);
            color: white;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s ease;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
        }
        
        .btn:hover {
            opacity: 0.9;
            transform: translateY(-2px);
        }
        
        .btn:active {
            transform: translateY(1px);
        }
        
        .btn.secondary {
            background: linear-gradient(to right, #5a6268, #6c757d);
        }
        
        .btn.warning {
            background: linear-gradient(to right, #ff416c, #ff4b2b);
        }
        
        .btn i {
            font-size: 1.1em;
        }
        
        .info-panel {
            background: linear-gradient(145deg, #f8f9fa, #e9ecef);
            padding: 15px;
            border-radius: 8px;
            font-size: 0.95rem;
        }
        
        .formula {
            font-family: monospace;
            background: #f1f8ff;
            padding: 10px;
            border-radius: 5px;
            border-left: 4px solid #3a7bd5;
            margin: 10px 0;
            white-space: nowrap;
            overflow-x: auto;
        }
        
        .dimension {
            display: flex;
            align-items: center;
            margin: 8px 0;
            font-size: 0.95rem;
        }
        
        .dimension span {
            font-weight: bold;
            color: #3a7bd5;
            margin-right: 8px;
        }
        
        .dimension .value {
            font-weight: 600;
            background: #e8f4ff;
            padding: 3px 8px;
            border-radius: 4px;
        }
        
        .instructions {
            background: #fff8e1;
            border-left: 4px solid #ffc107;
            padding: 15px;
            border-radius: 0 6px 6px 0;
            margin-top: 15px;
        }
        
        .instructions h3 {
            color: #d49b00;
            margin-bottom: 8px;
            font-size: 1.1rem;
        }
        
        .instructions ul {
            padding-left: 20px;
            margin-top: 10px;
        }
        
        .instructions li {
            margin-bottom: 8px;
            line-height: 1.4;
        }
        
        .model-gallery {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 15px;
        }
        
        .model-thumb {
            width: 70px;
            height: 70px;
            border-radius: 8px;
            background: #e0eaf5;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all 0.2s;
            border: 2px solid transparent;
        }
        
        .model-thumb:hover {
            transform: scale(1.05);
            border-color: #3a7bd5;
        }
        
        .model-thumb.active {
            border-color: #ff416c;
            background: #ffeef2;
        }
        
        .model-thumb i {
            font-size: 1.8rem;
            color: #3a7bd5;
        }
        
        @media (max-width: 900px) {
            .main-content {
                flex-direction: column;
            }
            
            .controls {
                width: 100%;
                max-height: 40vh;
            }
        }