: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;
            --error-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);
        }
         
        /* Chart Container */
        .chart-container {
            position: relative;
            height: 400px;
            width: 100%;
            margin: 2rem 0;
        }
        
        /* Spectral Summary */
        .spectral-summary {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }
        
        .spectral-item {
            background: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }
        
        .spectral-item h4 {
            font-size: 1rem;
            color: var(--text-muted);
            margin-bottom: 0.5rem;
        }
        
        .spectral-item .value {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary-color);
        }
        
        .spectral-item .detail {
            font-size: 0.9rem;
            color: var(--text-muted);
            margin-top: 0.5rem;
        }
        
       
        /* Responsive Adjustments */
        @media (max-width: 768px) { 
            .spectral-summary {
                grid-template-columns: 1fr;
            }
        }
        
        /* Toggle switch for calculation modes */
        .analysis-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;
        }
         
        
        /* Range slider styling */
        .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 styling */
        .input-group {
            margin-bottom: 1rem;
        }
        
        /* Mode-specific form styling */
        .mode-form {
            display: none;
        }
        
        .mode-form.active {
            display: block;
        }
        
        /* Peaks table */
        .peaks-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        
        .peaks-table th, .peaks-table td {
            padding: 0.75rem;
            text-align: left;
            border-bottom: 1px solid var(--border-color);
        }
        
        .peaks-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .peaks-table tr:hover {
            background-color: rgba(44, 125, 160, 0.05);
        }
     
        /* File Upload Area */
        .file-upload-area {
            border: 2px dashed var(--border-color);
            border-radius: 8px;
            padding: 2rem;
            text-align: center;
            background-color: var(--light-gray);
            transition: all 0.3s;
            cursor: pointer;
            margin-bottom: 1.5rem;
            position: relative;
        }
        
        .file-upload-area:hover {
            border-color: var(--primary-color);
            background-color: rgba(44, 125, 160, 0.05);
        }
        
        .file-upload-area i {
            font-size: 3rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        
        .file-upload-text {
            font-weight: 600;
            margin-bottom: 0.5rem;
        }
        
        .file-upload-hint {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        .file-preview {
            margin-top: 1rem;
            text-align: left;
            background-color: white;
            border-radius: 6px;
            padding: 1rem;
            border: 1px solid var(--border-color);
            max-height: 200px;
            overflow-y: auto;
        }
        
        .file-preview-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--primary-color);
        }
        
        .file-preview-content {
            font-family: monospace;
            font-size: 0.85rem;
            white-space: pre-wrap;
            word-break: break-all;
        }
        
        /* Sample Spectra */
        .sample-spectra {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        
        .sample-spectrum {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            padding: 1rem;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .sample-spectrum:hover, .sample-spectrum.selected {
            border-color: var(--primary-color);
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
            background-color: rgba(44, 125, 160, 0.05);
        }
        
        .sample-spectrum i {
            font-size: 2rem;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
        }
        
        .sample-name {
            font-weight: 600;
            margin-bottom: 0.25rem;
        }
        
        .sample-type {
            color: var(--text-muted);
            font-size: 0.85rem;
        }
        
        /* Advanced Options */
        .advanced-options {
            background-color: var(--light-gray);
            border-radius: 8px;
            padding: 1.5rem;
            margin: 1.5rem 0;
        }
        
        .advanced-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .advanced-content {
            display: none;
        }
        
        .advanced-content.show {
            display: block;
        }
        
        /* Export buttons */
        .export-buttons {
            display: flex;
            gap: 0.5rem;
            margin-top: 1rem;
            flex-wrap: wrap;
        }
        
        .export-btn {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            padding: 0.5rem 1rem;
            transition: all 0.3s;
            color: var(--text-color);
            font-size: 0.9rem;
        }
        
        .export-btn:hover {
            background-color: var(--light-gray);
            color: var(--primary-color);
        }
        
        /* Error message */
        .error-message {
            color: var(--error-color);
            background-color: rgba(220, 53, 69, 0.1);
            border: 1px solid rgba(220, 53, 69, 0.2);
            border-radius: 6px;
            padding: 0.75rem;
            margin: 1rem 0;
            display: none;
        }
        
        .error-message.show {
            display: block;
        }