body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            margin: 0;
            padding: 20px;
            background-color: #f0f4f8;
            color: #333;
        }
        .container {
            max-width: 900px;
            margin: 0 auto;
            background-color: #ffffff;
            border-radius: 12px;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
            padding: 30px;
        }
        h1 {
            text-align: center;
            color: #2c3e50;
            margin-bottom: 30px;
        }
        .tabs {
            display: flex;
            justify-content: center;
            margin-bottom: 30px;
            border-bottom: 2px solid #ecf0f1;
            flex-wrap: wrap;
        }
        .tab {
            padding: 12px 20px;
            background-color: #ecf0f1;
            border: none;
            cursor: pointer;
            transition: background-color 0.3s;
            border-radius: 6px 6px 0 0;
            margin: 0 2px 0 0;
            font-size: 14px;
            white-space: nowrap;
        }
        .tab.active {
            background-color: #3498db;
            color: white;
        }
        .tab-content {
            display: none;
        }
        .tab-content.active {
            display: block;
        }
        .calculator-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 25px;
            margin: 20px 0;
        }
        .calc-card {
            padding: 25px;
            background-color: #f8f9fa;
            border-radius: 8px;
            border: 1px solid #ddd;
        }
        .calc-card h3 {
            margin-top: 0;
            color: #2c3e50;
            text-align: center;
        }
        .input-group {
            margin: 15px 0;
        }
        .input-group label {
            display: block;
            margin-bottom: 5px;
            font-weight: 500;
            color: #555;
        }
        .input-group input {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 16px;
            box-sizing: border-box;
        }
        .calculate-btn {
            width: 100%;
            padding: 15px;
            font-size: 16px;
            background-color: #3498db;
            color: white;
            border: none;
            border-radius: 6px;
            cursor: pointer;
            margin: 15px 0;
            transition: background-color 0.3s;
        }
        .calculate-btn:hover {
            background-color: #2980b9;
        }
        .result {
            margin-top: 15px;
            padding: 15px;
            background-color: #e8f5e8;
            border-radius: 6px;
            border-left: 4px solid #2ecc71;
            display: none;
        }
        .result.show {
            display: block;
        }
        .result-value {
            font-size: 20px;
            font-weight: bold;
            color: #27ae60;
            text-align: center;
        }
        .explanation {
            margin-top: 10px;
            padding: 10px;
            background-color: #f0f0f0;
            border-radius: 4px;
            font-size: 14px;
        }
        .example {
            background-color: #e3f2fd;
            padding: 15px;
            border-radius: 6px;
            margin: 15px 0;
        }
        .example h4 {
            margin-top: 0;
            color: #1976d2;
        }
        .back-link {
            display: inline-block;
            margin-bottom: 20px;
            color: #3498db;
            text-decoration: none;
            transition: color 0.3s;
        }
        .back-link:hover {
            color: #2980b9;
        }
        .formula {
            background-color: #f8f9fa;
            padding: 10px;
            border-radius: 4px;
            font-family: monospace;
            text-align: center;
            margin: 10px 0;
            border: 1px dashed #6c757d;
        }
        .tip {
            background-color: #fff3cd;
            border: 1px solid #ffeaa7;
            padding: 10px;
            border-radius: 4px;
            margin: 10px 0;
        }
        .comparison-table {
            width: 100%;
            border-collapse: collapse;
            margin: 20px 0;
        }
        .comparison-table th,
        .comparison-table td {
            padding: 12px;
            text-align: left;
            border-bottom: 1px solid #ddd;
        }
        .comparison-table th {
            background-color: #f8f9fa;
            font-weight: 600;
        }

        /* Cross-linking styles */
        .cross-links-section {
            max-width: 1000px;
            margin: 40px auto 20px;
            background-color: #ffffff;
            border-radius: 12px;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
            padding: 30px;
        }
        
        .cross-links-section h2 {
            text-align: center;
            color: #2c3e50;
            margin-bottom: 30px;
            font-size: 1.8em;
            border-bottom: 3px solid #3498db;
            padding-bottom: 15px;
        }
        
        .cross-link-category {
            margin-bottom: 30px;
        }
        
        .cross-link-category h3 {
            color: #2c3e50;
            margin-bottom: 15px;
            font-size: 1.3em;
            padding-left: 10px;
            border-left: 4px solid #3498db;
        }
        
        .cross-link-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 15px;
        }
        
        .cross-link-card {
            display: block;
            text-decoration: none;
            color: #34495e;
            background: #f8f9fa;
            border: 2px solid #e9ecef;
            border-radius: 8px;
            padding: 15px;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }
        
        .cross-link-card:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 20px rgba(52, 152, 219, 0.15);
            border-color: #3498db;
            background: #e3f2fd;
            color: #2c3e50;
        }
        
        .cross-link-card span {
            font-weight: 500;
            display: block;
            line-height: 1.4;
        }
        
        .cross-link-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 4px;
            height: 100%;
            background: #3498db;
            transform: scaleY(0);
            transition: transform 0.3s ease;
        }
        
        .cross-link-card:hover::before {
            transform: scaleY(1);
        }
        
        @media (max-width: 768px) {
            .cross-links-section {
                margin: 20px;
                padding: 20px;
            }
            
            .cross-link-grid {
                grid-template-columns: 1fr;
                gap: 12px;
            }
            
            .cross-link-card {
                padding: 12px;
            }
        }