body {
            margin: 0;
            padding: 20px;
            font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
            color: #ffffff;
            min-height: 100vh;
            overflow-x: auto;
        }

        .container {
            max-width: 1400px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 320px 1fr;
            gap: 30px;
            align-items: start;
        }

        .title {
            text-align: center;
            font-size: 32px;
            font-weight: bold;
            margin-bottom: 30px;
            color: #ffd700;
            text-shadow: 0 0 20px rgba(255, 215, 0, 0.5);
            grid-column: 1 / -1;
        }

        .control-panel {
            background: rgba(255, 255, 255, 0.1);
            border-radius: 15px;
            padding: 25px;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .control-group {
            margin-bottom: 25px;
        }

        .control-group h3 {
            font-size: 18px;
            margin-bottom: 15px;
            color: #ffd700;
            border-bottom: 2px solid #ffd700;
            padding-bottom: 8px;
        }

        .slider-container {
            margin-bottom: 15px;
        }

        .slider-container label {
            display: block;
            font-size: 16px;
            margin-bottom: 8px;
            color: #e0e0e0;
        }

        .slider {
            width: 100%;
            height: 8px;
            border-radius: 4px;
            background: rgba(255, 255, 255, 0.2);
            outline: none;
            -webkit-appearance: none;
        }

        .slider::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: #ffd700;
            cursor: pointer;
            box-shadow: 0 0 10px rgba(255, 215, 0, 0.5);
        }

        .button-group {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }

        .btn {
            padding: 12px 20px;
            border: none;
            border-radius: 8px;
            background: #1976d2;
            color: white;
            font-size: 16px;
            cursor: pointer;
            transition: all 0.3s ease;
            flex: 1;
            min-width: 80px;
        }

        .btn:hover {
            background: #1565c0;
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(25, 118, 210, 0.3);
        }

        .btn.active {
            background: #ff5722;
        }

        .canvas-container {
            background: rgba(0, 0, 0, 0.3);
            border-radius: 15px;
            padding: 20px;
            border: 2px solid rgba(255, 215, 0, 0.3);
            position: relative;
            min-height: 600px;
        }

        #lightCanvas {
            width: 100%;
            height: 600px;
            border-radius: 10px;
            background: radial-gradient(circle at center, rgba(26, 26, 46, 0.8) 0%, rgba(15, 52, 96, 0.9) 100%);
            cursor: crosshair;
        }

        .info-panel {
            position: absolute;
            top: 20px;
            right: 20px;
            background: rgba(0, 0, 0, 0.7);
            padding: 15px;
            border-radius: 10px;
            font-size: 14px;
            max-width: 250px;
        }

        .measurement-display {
            background: rgba(76, 175, 80, 0.2);
            border: 1px solid #4caf50;
            border-radius: 8px;
            padding: 12px;
            margin-top: 15px;
        }

        .measurement-display h4 {
            margin: 0 0 10px 0;
            color: #4caf50;
            font-size: 16px;
        }

        .value-display {
            font-family: 'Courier New', monospace;
            font-size: 14px;
            color: #ffffff;
            background: rgba(0, 0, 0, 0.5);
            padding: 8px;
            border-radius: 4px;
            margin: 5px 0;
        }

        .legend {
            display: flex;
            gap: 20px;
            margin-top: 15px;
            flex-wrap: wrap;
        }

        .legend-item {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 14px;
        }

        .legend-color {
            width: 20px;
            height: 4px;
            border-radius: 2px;
        }

        .application-examples {
            grid-column: 1 / -1;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 15px;
            padding: 25px;
            margin-top: 30px;
        }

        .application-examples h3 {
            font-size: 24px;
            color: #ffd700;
            margin-bottom: 20px;
            text-align: center;
        }

        .examples-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 20px;
        }

        .example-card {
            background: rgba(0, 0, 0, 0.3);
            border-radius: 10px;
            padding: 20px;
            border: 1px solid rgba(255, 215, 0, 0.2);
        }

        .example-card h4 {
            color: #ff9800;
            font-size: 18px;
            margin-bottom: 10px;
        }

        .example-card p {
            font-size: 16px;
            line-height: 1.6;
            color: #e0e0e0;
        }

         .footer {
            background: linear-gradient(to right, #2c3e50, #1a2530);
            color: #ecf0f1;
            text-align: center;
            padding: 20px;
            margin-top: 25px;
            border-radius: 0 0 10px 10px;
        }

        @media (max-width: 768px) {
            .container {
                grid-template-columns: 1fr;
                gap: 20px;
            }
            
            .title {
                font-size: 28px;
            }
            
            #lightCanvas {
                height: 400px;
            }
        }