: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;
        }
        
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: white;
            color: var(--text-color);
            line-height: 1.6;
        }
        
        .container {
            max-width: 1200px;
        }
        
        .navbar {
            background-color: white;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            border-bottom: 1px solid var(--border-color);
            padding: 0.75rem 0;
        }
        
        .navbar-brand {
            font-weight: 700;
            color: var(--primary-color);
            font-size: 1.5rem;
        }
        
        .nav-link {
            color: #555;
            font-weight: 500;
            padding: 0.5rem 1rem;
            border-radius: 6px;
        }
        
        .nav-link:hover, .nav-link.active {
            color: var(--primary-color);
            background-color: rgba(44, 125, 160, 0.1);
        }
        
        .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);
        }
         
        .calculation-modes {
            display: flex;
            background-color: var(--light-gray);
            border-radius: 6px;
            padding: 4px;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
        }
        
        .mode-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;
        }
        
        .mode-btn.active {
            background-color: var(--primary-color);
            color: white;
        }
          
        
        .mode-form {
            display: none;
        }
        
        .mode-form.active {
            display: block;
        }
        
        .comparison-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        
        .comparison-table th, .comparison-table td {
            padding: 0.75rem;
            text-align: left;
            border-bottom: 1px solid var(--border-color);
        }
        
        .comparison-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .comparison-table tr:hover {
            background-color: rgba(44, 125, 160, 0.05);
        }
        
        .generating-indicator {
            display: none;
            text-align: center;
            padding: 1rem;
            color: var(--primary-color);
            font-weight: 600;
        }
         
        .standard-points {
            margin-bottom: 1.5rem;
        }
        
        .standard-point {
            display: flex;
            gap: 10px;
            margin-bottom: 10px;
            align-items: center;
        }
        
        .standard-point input {
            flex: 1;
        }
        
        .point-actions {
            display: flex;
            gap: 5px;
        }
        
        .point-action-btn {
            background: none;
            border: none;
            color: var(--text-muted);
            cursor: pointer;
            padding: 5px;
            border-radius: 4px;
            transition: all 0.3s;
        }
        
        .point-action-btn:hover {
            background-color: var(--light-gray);
            color: var(--primary-color);
        }
        
        .add-point-btn {
            margin-top: 10px;
        }
        
        .unknown-sample {
            display: flex;
            gap: 10px;
            margin-bottom: 10px;
            align-items: center;
        }
        
        .unknown-sample input {
            flex: 1;
        }
        
        .equation-box {
            background-color: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-bottom: 1.5rem;
            font-family: 'Courier New', monospace;
            font-size: 1.1rem;
        }
        
        .fit-quality {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 1rem;
            margin-bottom: 1.5rem;
        }
        
        .fit-quality-item {
            text-align: center;
            padding: 1rem;
            background-color: white;
            border-radius: 8px;
            border: 1px solid var(--border-color);
        }
        
        .fit-quality-value {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary-color);
        }
        
        .fit-quality-label {
            font-size: 0.9rem;
            color: var(--text-muted);
        }
        
        .prediction-results {
            margin-top: 1.5rem;
        }
        
        .prediction-table {
            width: 100%;
            border-collapse: collapse;
        }
        
        .prediction-table th, .prediction-table td {
            padding: 0.75rem;
            text-align: left;
            border-bottom: 1px solid var(--border-color);
        }
        
        .prediction-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .data-points-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        
        .data-points-table th, .data-points-table td {
            padding: 0.75rem;
            text-align: center;
            border-bottom: 1px solid var(--border-color);
        }
        
        .data-points-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .residuals-container {
            margin-top: 1.5rem;
        }
        
        .validation-alert {
            background-color: rgba(255, 193, 7, 0.1);
            border-left: 4px solid var(--warning-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        
        .confidence-interval {
            background-color: rgba(44, 125, 160, 0.05);
            border-left: 4px solid var(--primary-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        
        .advanced-stats {
            margin-top: 1.5rem;
        }
        
        .stats-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1rem 0;
        }
        
        .stats-table th, .stats-table td {
            padding: 0.75rem;
            text-align: left;
            border-bottom: 1px solid var(--border-color);
        }
        
        .stats-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }