: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;
        }
         
        .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);
        }
         
        /* Toggle switch for calculation modes */
        .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-specific form styling */
        .mode-form {
            display: none;
        }
        
        .mode-form.active {
            display: block;
        }
        
        /* Comparison table */
        .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 formula display */
        .chemical-formula {
            font-family: 'Courier New', monospace;
            font-size: 1.2rem;
            background-color: #f8f9fa;
            padding: 0.5rem 1rem;
            border-radius: 4px;
            display: inline-block;
            margin: 0.5rem 0;
        }
        
        /* Generating indicator */
        .generating-indicator {
            display: none;
            padding: 1rem;
            text-align: center;
            background-color: rgba(44, 125, 160, 0.1);
            border-radius: 6px;
            margin: 1rem 0;
        }
        
        /* Examples grid */
        .examples-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .example-item {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            padding: 1rem;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .example-item:hover {
            border-color: var(--primary-color);
            transform: translateY(-2px);
        }
        
        .example-formula {
            font-family: 'Courier New', monospace;
            font-weight: bold;
            margin-bottom: 0.5rem;
        }
        
        .example-name {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        /* Data input table */
        .data-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1rem 0;
        }
        
        .data-table th, .data-table td {
            border: 1px solid #ddd;
            padding: 8px;
            text-align: center;
        }
        
        .data-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .data-input {
            width: 100%;
            border: none;
            text-align: center;
            background-color: transparent;
        }
        
        .data-input:focus {
            outline: none;
            background-color: rgba(44, 125, 160, 0.1);
        }
        
        /* SNR quality indicators */
        .quality-indicator {
            display: inline-block;
            padding: 0.25rem 0.75rem;
            border-radius: 20px;
            font-weight: 600;
            font-size: 0.85rem;
        }
        
        .quality-excellent {
            background-color: rgba(40, 167, 69, 0.1);
            color: #28a745;
        }
        
        .quality-good {
            background-color: rgba(255, 193, 7, 0.1);
            color: #ffc107;
        }
        
        .quality-fair {
            background-color: rgba(253, 126, 20, 0.1);
            color: #fd7e14;
        }
        
        .quality-poor {
            background-color: rgba(220, 53, 69, 0.1);
            color: #dc3545;
        }
        
        /* Signal visualization */
        .signal-viz {
            text-align: center;
            margin: 1.5rem 0;
            padding: 1rem;
            background-color: white;
            border-radius: 6px;
            border: 1px solid var(--border-color);
        }
        
        .signal-placeholder {
            height: 200px;
            display: flex;
            align-items: center;
            justify-content: center;
            background-color: #f8f9fa;
            border-radius: 4px;
            color: var(--text-muted);
        }
        
        /* SNR parameters */
        .snr-params {
            background-color: white;
            border-radius: 6px;
            padding: 1rem;
            margin-bottom: 1rem;
            border: 1px solid var(--border-color);
        }
        
        .snr-params h5 {
            color: var(--primary-color);
            margin-bottom: 0.5rem;
        }