/* Custom styles for this calculator */
        .faq-section {
            background: var(--background-secondary);
            padding: var(--spacing-lg);
            margin-bottom: var(--spacing-lg);
            border-radius: var(--radius-lg);
            border: 1px solid #e0e0e0;
            box-shadow: var(--shadow-light);
        }

        .faq-section h3 {
            color: var(--primary-color);
            margin-bottom: var(--spacing-md);
            font-size: var(--font-size-lg);
            font-weight: 600;
        }
        
        .faq-section p {
            color: var(--text-secondary);
            line-height: 1.6;
        }

        .related-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: var(--spacing-lg);
            margin-top: var(--spacing-lg);
        }

        .related-card {
            background: var(--background-secondary);
            padding: var(--spacing-lg);
            border-radius: var(--radius-lg);
            text-decoration: none;
            color: var(--text-primary);
            transition: all var(--transition-normal);
            border: 1px solid #e0e0e0;
            display: block;
            text-align: center;
        }

        .related-card:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-medium);
            border-color: var(--secondary-color);
        }

        .related-card h3 {
            color: var(--secondary-color);
            margin-bottom: var(--spacing-sm);
            font-size: var(--font-size-lg);
            font-weight: 600;
        }
        
        .related-card p {
            color: var(--text-secondary);
            font-size: var(--font-size-sm);
        }

        .mode-selector {
            display: flex;
            gap: 10px;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .mode-btn {
            padding: 12px 24px;
            border: none;
            border-radius: 25px;
            background: #f0f0f0;
            color: #333;
            cursor: pointer;
            transition: all 0.3s ease;
            font-weight: 500;
        }

        .mode-btn.active {
            background: var(--accent-color);
            color: var(--text-white);
        }

        .mode-btn:hover {
            background: var(--accent-color);
            color: var(--text-white);
        }

        .calculator-section {
            display: none;
        }

        .calculator-section.active {
            display: block;
        }

        .info-box {
            background: #e8f4fd;
            padding: 20px;
            border-radius: 10px;
            margin-bottom: 30px;
            border-left: 4px solid #667eea;
        }

        .info-box h3 {
            color: #667eea;
            margin-bottom: 15px;
        }

        .info-box p {
            color: #333;
            line-height: 1.6;
            margin-bottom: 10px;
        }

        .input-group {
            margin-bottom: 20px;
        }

        .input-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: #333;
        }

        .input-group input, .input-group select {
            width: 100%;
            padding: 12px;
            border: 2px solid #e0e0e0;
            border-radius: 10px;
            font-size: 16px;
            transition: border-color 0.3s ease;
        }

        .input-group input:focus, .input-group select:focus {
            outline: none;
            border-color: #667eea;
        }

        .calculate-btn {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 10px;
            font-size: 18px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            margin-bottom: 20px;
        }

        .calculate-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 20px rgba(0,0,0,0.2);
        }

        .result {
            background: #f8f9fa;
            padding: 20px;
            border-radius: 10px;
            margin-top: 20px;
            display: none;
        }

        .result.show {
            display: block;
        }

        .result h3 {
            color: #667eea;
            margin-bottom: 15px;
        }

        .result-item {
            display: flex;
            justify-content: space-between;
            margin-bottom: 10px;
            padding: 10px;
            background: white;
            border-radius: 8px;
        }

        .result-label {
            font-weight: 600;
            color: #333;
        }

        .result-value {
            font-weight: 700;
            color: #667eea;
        }

        .decay-chart {
            width: 100%;
            height: 300px;
            background: #f8f9fa;
            border-radius: 10px;
            margin: 20px 0;
            position: relative;
            overflow: hidden;
        }

        .decay-bar {
            position: absolute;
            bottom: 0;
            width: 100%;
            background: linear-gradient(90deg, #667eea, #764ba2);
            transition: height 1s ease;
        }

        .decay-label {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-weight: bold;
            color: #333;
            text-align: center;
        }

        .time-table {
            width: 100%;
            border-collapse: collapse;
            margin-top: 15px;
            background: white;
            border-radius: 8px;
            overflow: hidden;
        }

        .time-table th, .time-table td {
            padding: 12px;
            text-align: center;
            border-bottom: 1px solid #e0e0e0;
        }

        .time-table th {
            background: #667eea;
            color: white;
            font-weight: 600;
        }

        .time-table tr:hover {
            background: #f8f9fa;
        }

        .tips {
            background: #e8f4fd;
            padding: 20px;
            border-radius: 10px;
            margin-top: 20px;
        }

        .tips h4 {
            color: #667eea;
            margin-bottom: 10px;
        }

        .tips ul {
            list-style: none;
            padding-left: 0;
        }

        .tips li {
            margin-bottom: 8px;
            padding-left: 20px;
            position: relative;
        }

        .tips li:before {
            content: "⚛️";
            position: absolute;
            left: 0;
        }

        .back-link {
            display: inline-block;
            margin-top: 20px;
            color: #667eea;
            text-decoration: none;
            font-weight: 600;
            transition: color 0.3s ease;
        }

        .back-link:hover {
            color: #764ba2;
        }

        .warning {
            background: #fff3cd;
            border: 1px solid #ffeaa7;
            color: #856404;
            padding: 15px;
            border-radius: 8px;
            margin-bottom: 20px;
        }

        @media (max-width: 600px) {
            .header h1 {
                font-size: 2em;
            }
            
            .mode-selector {
                flex-direction: column;
            }
            
            .mode-btn {
                text-align: center;
            }
            
            .result-item {
                flex-direction: column;
                gap: 5px;
            }
        }