:root {
            --primary-color: #2c3e50;
            --accent-color: #3498db;
            --bg-color: #f0f2f5;
            --card-bg: #ffffff;
            --text-color: #333;
            --panel-bg: #f8f9fa;
        }

        body {
            font-family: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Microsoft YaHei', sans-serif;
            background-color: var(--bg-color);
            color: var(--text-color);
            line-height: 1.6;
            margin: 0;
            }

        .page-container { margin: 20px; }

        .header-wrapper {
            text-align: center;
            margin-bottom: 30px;
        }

        h1 {
            color: var(--primary-color);
            font-size: 2.2rem;
            margin-bottom: 10px;
            font-weight: 700;
        }

        .back-btn {
            display: inline-flex;
            align-items: center;
            padding: 10px 20px;
            background-color: var(--primary-color);
            color: white !important;
            text-decoration: none;
            border-radius: 8px;
            font-weight: 500;
            transition: all 0.3s ease;
            border: none;
            cursor: pointer;
            margin-bottom: 20px;
        }

        .back-btn:hover {
            background-color: var(--accent-color);
            transform: translateX(-5px);
        }

        .description {
            background: #fdfdfd;
            padding: 20px;
            border-left: 4px solid var(--accent-color);
            margin-bottom: 30px;
            border-radius: 0 8px 8px 0;
        }

        /* Simulation Wrapper for Responsive Scaling */
        .sim-wrapper {
            justify-content: center;
            align-items: center;
            margin: 40px 0;
            background: #fff;
            border-radius: 12px;
            padding: 20px;
            box-shadow: inset 0 0 10px rgba(0,0,0,0.02);
            overflow: hidden;
        }

        #total {
            position: relative;
            width: 700px;
            height: 400px;
            background-color: var(--panel-bg);
            border: 1px solid #ddd;
            transform-origin: center center;
        }

        #canvas {
            position: absolute;
            left: 0;
            top: 0;
            width: 480px;
            height: 400px;
            background: #fff;
        }

        #panel {
            position: absolute;
            left: 480px;
            top: 0;
            width: 220px;
            height: 400px;
            
            background: var(--panel-bg);
            border-left: 1px solid #eee;
            font-size: 0.9rem;
        }

        #panel div {
            position: absolute;
            width: 190px;
            left: 15px;
        }

        button {
            width: 100%;
            padding: 8px;
            border-radius: 4px;
            border: 1px solid #ccc;
            cursor: pointer;
            font-weight: 600;
            transition: opacity 0.2s;
            margin-bottom: 10px;
        }

        button:hover { opacity: 0.9; }

        input[type="text"] {
            position: absolute;
            left: 100px;
            width: 50px;
            padding: 3px;
            border: 1px solid #ccc;
            border-radius: 4px;
        }

        label { cursor: pointer; }

        .wave1 { color: #3b82f6; font-weight: bold; }
        .wave2 { color: #ef4444; font-weight: bold; }
        .sum-wave { color: #1e293b; font-weight: bold; }

        .footer-info {
            font-size: 0.85rem;
            color: #7f8c8d;
            text-align: right;
            margin-top: 20px;
        }

        @media (max-width: 740px) {
            .page-container { margin: 10px; padding: 20px; }
            .sim-wrapper { padding: 5px; }
        }