: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;
            --chemistry-color: #8a2be2;
        }
         
        .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);
        }
         
        /* Chemical Summary */
        .chemical-summary {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }
        
        .chemical-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);
        }
        
        .chemical-item h4 {
            font-size: 1rem;
            color: var(--text-muted);
            margin-bottom: 0.5rem;
        }
        
        .chemical-item .value {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--chemistry-color);
        }
        
        .chemical-item .detail {
            font-size: 0.9rem;
            color: var(--text-muted);
            margin-top: 0.5rem;
        }
         
        /* Formula examples */
        .formula-examples {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin-top: 1rem;
        }
        
        .formula-example {
            background-color: rgba(138, 43, 226, 0.1);
            border: 1px solid rgba(138, 43, 226, 0.2);
            border-radius: 4px;
            padding: 0.5rem 1rem;
            font-family: monospace;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .formula-example:hover {
            background-color: rgba(138, 43, 226, 0.2);
            transform: translateY(-2px);
        }
        
        /* Complex formula examples */
        .complex-formula-examples {
            margin-top: 1rem;
            padding: 1rem;
            background-color: rgba(138, 43, 226, 0.05);
            border-radius: 6px;
        }
        
        .complex-formula-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--chemistry-color);
        }
        
        /* Periodic table element */
        .periodic-element {
            display: inline-block;
            width: 60px;
            height: 60px;
            margin: 5px;
            text-align: center;
            border: 1px solid #ddd;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .periodic-element:hover {
            transform: scale(1.05);
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        }
        
        .element-symbol {
            font-weight: bold;
            font-size: 1.2rem;
            margin-top: 8px;
        }
        
        .element-number {
            font-size: 0.7rem;
            color: var(--text-muted);
        }
        
        .element-name {
            font-size: 0.6rem;
            margin-top: -5px;
        }
         
        /* Chemical formula styling */
        .chemical-formula {
            font-family: 'Times New Roman', serif;
            font-size: 1.5rem;
            font-weight: bold;
            color: var(--chemistry-color);
        }
        
        .chemical-subscript {
            font-size: 0.8em;
            vertical-align: sub;
        }
        
        /* Element composition table */
        .composition-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        
        .composition-table th, .composition-table td {
            padding: 0.75rem;
            text-align: left;
            border-bottom: 1px solid var(--border-color);
        }
        
        .composition-table th {
            background-color: var(--light-gray);
            font-weight: 600;
        }
        
        .composition-table tr:hover {
            background-color: rgba(138, 43, 226, 0.05);
        }
        
        /* Formula input styling */
        .formula-input-container {
            position: relative;
        }
        
        .formula-preview {
            position: absolute;
            top: 50%;
            right: 15px;
            transform: translateY(-50%);
            font-family: 'Times New Roman', serif;
            font-size: 1.2rem;
            color: var(--text-muted);
        }