: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);
        }
           
        .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;
        }
         
        
        .form-range {
            width: 100%;
            height: 1rem;
            padding: 0;
            background-color: transparent;
            -webkit-appearance: none;
        }
        
        .form-range:focus {
            outline: none;
        }
        
        .form-range::-webkit-slider-thumb {
            width: 1rem;
            height: 1rem;
            margin-top: -0.5rem;
            background-color: var(--primary-color);
            border: 0;
            border-radius: 1rem;
            -webkit-appearance: none;
        }
        
        .form-range::-webkit-slider-runnable-track {
            width: 100%;
            height: 0.5rem;
            cursor: pointer;
            animate: 0.2s;
            background: var(--light-gray);
            border-radius: 0.5rem;
        }
        
        .slider-value {
            background-color: var(--primary-color);
            color: white;
            padding: 0.25rem 0.5rem;
            border-radius: 4px;
            font-size: 0.8rem;
            margin-left: 0.5rem;
        }
        
        .input-group {
            margin-bottom: 1rem;
        }
        
        .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);
        }
        
        .chemical-info {
            background-color: rgba(169, 214, 229, 0.1);
            border-radius: 8px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            border-left: 4px solid var(--primary-color);
        }
        
        .chemical-info h4 {
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        
        .chemical-formula {
            font-family: 'Times New Roman', serif;
            font-style: italic;
            font-size: 1.1rem;
            background-color: rgba(255,255,255,0.7);
            padding: 0.25rem 0.5rem;
            border-radius: 4px;
            display: inline-block;
        }
         
        .range-container {
            display: flex;
            align-items: center;
            margin-top: 0.5rem;
        }
        
        .range-value {
            min-width: 60px;
            text-align: right;
            font-weight: 600;
            color: var(--primary-color);
        }
        
        .pka-inputs {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 10px;
        }
        
        .pka-input {
            flex: 1;
            min-width: 120px;
        }
        
        .accuracy-warning {
            color: var(--warning-color);
            font-size: 0.85rem;
            margin-top: 5px;
        }
        
        .extreme-warning {
            color: var(--danger-color);
            font-size: 0.85rem;
            margin-top: 5px;
            font-weight: 600;
        }