body {
            background-color: #f8f9fa;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            padding: 20px;
        }
        .container {
            max-width: 1200px;
            margin: 0 auto;
        }
        .header {
            text-align: center;
            margin-bottom: 25px;
            color: #2c3e50;
            padding-bottom: 15px;
            border-bottom: 2px solid #3498db;
        }
        .card {
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
            margin-bottom: 20px;
            overflow: hidden;
        }
        .card-body {
            padding: 20px;
        }
        .card-header {
            background: linear-gradient(135deg, #3498db, #2c3e50);
            color: white;
            padding: 12px 20px;
            font-weight: bold;
        }
        .chart-container {
            height: 450px;
            position: relative;
        }
        .controls {
            display: flex;
            flex-wrap: wrap;
            gap: 20px;
            margin-top: 20px;
            justify-content: center;
        }
        .control-group {
            background: #e9f7fe;
            border-radius: 8px;
            padding: 15px;
            flex: 1;
            min-width: 250px;
        }
        .form-label {
            font-weight: bold;
            color: #2980b9;
        }
        .footer {
            text-align: center;
            margin-top: 30px;
            padding: 15px;
            background-color: #2c3e50;
            color: white;
            border-radius: 8px;
            font-size: 0.9em;
        }
        .formula-display {
            background: #f9f9f9;
            border-radius: 5px;
            padding: 15px;
            margin: 20px 0;
            border-left: 4px solid #3498db;
            font-size: 1.1em;
            overflow-x: auto;
            min-height: 60px;
            text-align: center;
        }
        .control-value {
            background: #3498db;
            color: white;
            width: 40px;
            text-align: center;
            border-radius: 4px;
            display: inline-block;
            font-weight: bold;
        }