:root { 
            --accent-color: #2c3e50;
            --light-gray: #f8f9fa;
            --dark-bg: #1a1a2e;
            --success-color: #2ecc71;
            --warning-color: #f39c12;
            --danger-color: #e74c3c;
            --prime-blue: #3498db;
            --prime-green: #2ecc71;
            --prime-purple: #9b59b6;
            --text-color: #333;
            --text-muted: #6c757d;
        }
        
 
         
        
        /* Search and Filter */
        .search-container {
            display: flex;
            gap: 15px;
            margin-bottom: 1.5rem;
        }
        
        .search-box {
            flex: 1;
            position: relative;
        }
        
        .search-box i {
            position: absolute;
            left: 50px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-muted);
        }
        
        .search-box input {
            padding-left: 45px;
        }
        
        .category-filter {
            width: 200px;
        }
        
        /* Formula Cards */
        .formulas-container {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
            margin-top: 1.5rem;
        }
        
        .formula-card {
            background: white;
            border-radius: 8px;
            border: 1px solid #ddd;
            padding: 1.5rem;
            transition: all 0.3s;
            cursor: pointer;
            height: 100%;
            display: flex;
            flex-direction: column;
        }
        
        .formula-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            border-color: var(--primary-color);
        }
        
        .formula-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 1rem;
        }
        
        .formula-title {
            font-weight: 600;
            color: var(--primary-color);
            margin: 0;
        }
        
        .formula-category {
            display: inline-block;
            padding: 3px 8px;
            border-radius: 4px;
            font-size: 0.8rem;
            font-weight: 500;
        }
        
        .category-math {
            background-color: rgba(52, 152, 219, 0.1);
            color: var(--primary-color);
        }
        
        .category-physics {
            background-color: rgba(231, 76, 60, 0.1);
            color: var(--danger-color);
        }
        
        .category-chemistry {
            background-color: rgba(46, 204, 113, 0.1);
            color: var(--prime-green);
        }
        
        .category-algebra {
            background-color: rgba(155, 89, 182, 0.1);
            color: var(--prime-purple);
        }
        
        .category-calculus {
            background-color: rgba(243, 156, 18, 0.1);
            color: var(--warning-color);
        }
        
        .formula-content {
            flex: 1;
            display: flex;
            flex-direction: column;
            justify-content: center;
            min-height: 120px; overflow:auto
        }
        
        .formula-equation {
            font-size: 1.2rem;
            text-align: center;
            margin: 1rem 0;
            padding: 10px;
            background-color: var(--light-gray);
            border-radius: 6px;
        }
        
        .formula-description {
            color: var(--text-muted);
            font-size: 0.9rem;
            margin-top: 0.5rem;
        }
        
        .formula-variables {
            margin-top: 1rem;
            font-size: 0.85rem;
            color: var(--text-muted);
        }
        
        /* Formula Detail */
        .formula-detail {
            background-color: white;
            border-radius: 8px;
            border: 1px solid #ddd;
            padding: 2rem;
            margin-top: 1.5rem;
            display: none;
        }
        
        .formula-detail-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 1.5rem;
        }
        
        .formula-detail-title {
            font-size: 1.8rem;
            font-weight: 600;
            color: var(--primary-color);
            margin: 0;
        }
        
        .formula-detail-equation {
            font-size: 1.5rem;
            text-align: center;
            padding: 1.5rem;
            margin: 1.5rem 0;
            background-color: var(--light-gray);
            border-radius: 8px;
        }
        
        .formula-detail-body {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 2rem;
        }
        
        .formula-detail-description {
            line-height: 1.8;
        }
        
        .variables-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1rem 0;
        }
        
        .variables-table th {
            background-color: rgba(52, 152, 219, 0.1);
            color: var(--primary-color);
            font-weight: 600;
            padding: 0.75rem;
            text-align: left;
        }
        
        .variables-table td {
            padding: 0.75rem;
            border-bottom: 1px solid #eee;
        }
        
        .formula-applications ul {
            padding-left: 1.5rem;
        }
        
        .formula-applications li {
            margin-bottom: 0.5rem;
        }
        
        .formula-examples {
            background-color: rgba(52, 152, 219, 0.05);
            border-left: 4px solid var(--primary-color);
            padding: 1.5rem;
            border-radius: 0 8px 8px 0;
        }
        
        .example-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }
        
        .related-formulas {
            margin-top: 2rem;
        }
        
        .related-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--primary-color);
            padding-bottom: 0.5rem;
            border-bottom: 1px solid #ddd;
        }
        
        .related-list {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 15px;
        }
        
        .related-item {
            padding: 15px;
            border: 1px solid #ddd;
            border-radius: 6px;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .related-item:hover {
            background-color: rgba(52, 152, 219, 0.1);
            border-color: var(--primary-color);
        }
        
        .related-equation {
            font-size: 1.1rem;
            text-align: center;
            margin: 10px 0;
        }
        
        .related-name {
            font-weight: 500;
            text-align: center;
        }
        
        /* Categories Section */
        .categories-section {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            margin: 2rem 0;
        }
        
        .category-card {
            background-color: white;
            border-radius: 8px;
            border: 1px solid #ddd;
            padding: 1.5rem;
            transition: all 0.3s;
            cursor: pointer;
            text-align: center;
        }
        
        .category-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        
        .category-icon {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            margin: 0 auto 1rem;
        }
        
        .math-icon {
            background-color: rgba(52, 152, 219, 0.1);
            color: var(--primary-color);
        }
        
        .physics-icon {
            background-color: rgba(231, 76, 60, 0.1);
            color: var(--danger-color);
        }
        
        .chemistry-icon {
            background-color: rgba(46, 204, 113, 0.1);
            color: var(--prime-green);
        }
        
        .algebra-icon {
            background-color: rgba(155, 89, 182, 0.1);
            color: var(--prime-purple);
        }
        
        .calculus-icon {
            background-color: rgba(243, 156, 18, 0.1);
            color: var(--warning-color);
        }
        
        .geometry-icon {
            background-color: rgba(231, 76, 60, 0.1);
            color: var(--danger-color);
        }
        
        .category-name {
            font-weight: 600;
            margin-bottom: 0.5rem;
        }
        
        .category-count {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        
        /* Responsive Adjustments */
        @media (max-width: 768px) {
            .search-container {
                flex-direction: column;
            }
            
            .category-filter {
                width: 100%;
            }
            
            .formulas-container {
                grid-template-columns: 1fr;
            }
            
            .formula-detail-body {
                grid-template-columns: 1fr;
            }
        }