:root {
            --primary-color: #2c7da0;
            --secondary-color: #a9d6e5;
            --accent-color: #01497c;
            --light-gray: #f8f9fa;
            --border-color: #eaeaea;
            --text-color: #333;
            --text-muted: #6c757d;
            --success-color: #28a745;
            --warning-color: #ffc107;
            --danger-color: #dc3545;
        }
         
        .page-header {
            background: linear-gradient(135deg, rgba(169, 214, 229, 0.4) 0%, rgba(44, 125, 160, 0.4) 100%);
            padding: 1.5rem 0;
            margin-bottom: 2rem;
            border-bottom: 1px solid rgba(44, 125, 160, 0.2);
            position: relative;
            overflow: hidden;    color: var(--text-color);
        }
         
        .breadcrumb {
            background-color: transparent;
            padding: 0.5rem 0;
            margin-bottom: 0.5rem;
        }
        
        .breadcrumb-item a {
            color: var(--text-muted);
            text-decoration: none;
        }
        
        .breadcrumb-item.active {
            color: var(--text-color);
        }
         
        /* Dating Method Selection */
        .dating-methods {
            display: flex;
            background-color: var(--light-gray);
            border-radius: 6px;
            padding: 4px;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
        }
        
        .method-btn {
            flex: 1;
            text-align: center;
            padding: 0.75rem;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 600;
            min-width: 120px;
            margin: 2px;
        }
        
        .method-btn.active {
            background-color: var(--primary-color);
            color: white;
        }
        
        /* Chart Container */
        .chart-container {
            position: relative;
            height: 400px;
            width: 100%;
            margin: 2rem 0;
        }
        
        /* Stats Container */
        .stats-container {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .stat-card {
            background: white;
            border-radius: 8px;
            padding: 1.25rem;
            border: 1px solid var(--border-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            text-align: center;
        }
        
        .stat-value {
            font-size: 1.75rem;
            font-weight: 700;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
        }
        
        .stat-label {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
         
        
        /* Responsive Adjustments */
        @media (max-width: 768px) { 
            .stats-container {
                grid-template-columns: 1fr 1fr;
            }
            
            .dating-methods {
                flex-direction: column;
            }
            
            .method-btn {
                min-width: auto;
            }
        }
         
        /* Method-specific form styling */
        .method-form {
            display: none;
        }
        
        .method-form.active {
            display: block;
        }
        
        /* Uncertainty display */
        .uncertainty-display {
            background-color: rgba(44, 125, 160, 0.05);
            border-radius: 6px;
            padding: 1rem;
            margin: 1rem 0;
        }
        
        /* Geological timeline */
        .geological-timeline {
            background: linear-gradient(to right, #e9ecef, #dee2e6);
            height: 30px;
            border-radius: 4px;
            position: relative;
            margin: 1.5rem 0;
            overflow: hidden;
        }
        
        .timeline-period {
            position: absolute;
            height: 100%;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-weight: 600;
            font-size: 0.8rem;
            text-shadow: 0 1px 2px rgba(0,0,0,0.3);
        }
        
        .calculated-age-marker {
            position: absolute;
            top: -10px;
            width: 3px;
            height: 50px;
            background-color: #dc3545;
            z-index: 10;
        }
        
        .calculated-age-label {
            position: absolute;
            top: -35px;
            transform: translateX(-50%);
            background-color: #dc3545;
            color: white;
            padding: 2px 8px;
            border-radius: 4px;
            font-size: 0.8rem;
            font-weight: 600;
            white-space: nowrap;
        }
        
        /* Half-life visualization */
        .half-life-container {
            margin: 1.5rem 0;
        }
        
        .half-life-bar {
            height: 20px;
            background-color: #e9ecef;
            border-radius: 4px;
            overflow: hidden;
            position: relative;
        }
        
        .half-life-fill {
            height: 100%;
            background-color: var(--primary-color);
            transition: width 0.5s ease;
        }
        
        .half-life-labels {
            display: flex;
            justify-content: space-between;
            margin-top: 0.5rem;
            font-size: 0.8rem;
            color: var(--text-muted);
        }