: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:#333
        }
         
        
        .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);
        }
        
        /* Tool Card Styles */
        .tool-card {
            background: white;
            border-radius: 8px;
            border: 1px solid var(--border-color);
            padding: 2rem;
            margin-bottom: 1.5rem;
        }
        
        .tool-header {
            position: relative;
            padding-bottom: 15px;
            margin-bottom: 25px;
            border-bottom: 1px solid var(--border-color);
        }
        
        .tool-header h2 {
            font-weight: 600;
            color: var(--primary-color);
        }
        
        /* Timeline Styles */
        .timeline-container {
            position: relative;
            margin: 2rem 0;
        }
        
        .timeline {
            position: relative;
            max-width: 1200px;
            margin: 0 auto;
        }
        
        .timeline::after {
            content: '';
            position: absolute;
            width: 6px;
            background-color: var(--primary-color);
            top: 0;
            bottom: 0;
            left: 50%;
            margin-left: -3px;
        }
        
        .timeline-item {
            padding: 10px 40px;
            position: relative;
            width: 50%;
            box-sizing: border-box;
        }
        
        .timeline-item:nth-child(odd) {
            left: 0;
        }
        
        .timeline-item:nth-child(even) {
            left: 50%;
        }
        
        .timeline-item::after {
            content: '';
            position: absolute;
            width: 20px;
            height: 20px;
            right: -10px;
            background-color: white;
            border: 4px solid var(--primary-color);
            top: 15px;
            border-radius: 50%;
            z-index: 1;
        }
        
        .timeline-item:nth-child(even)::after {
            left: -10px;
        }
        
        .timeline-content {
            padding: 20px;
            background-color: white;
            position: relative;
            border-radius: 6px;
            border: 1px solid var(--border-color);
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            transition: all 0.3s;
        }
        
        .timeline-content:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        }
        
        .timeline-date {
            font-weight: 600;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
        }
        
        .timeline-title {
            font-weight: 600;
            margin-bottom: 0.5rem;
            font-size: 1.1rem;
        }
        
        .timeline-description {
            color: var(--text-muted);
            font-size: 0.95rem;
        }
        
        .timeline-category {
            display: inline-block;
            background-color: var(--light-gray);
            color: var(--text-muted);
            padding: 0.25rem 0.5rem;
            border-radius: 4px;
            font-size: 0.8rem;
            margin-top: 0.5rem;
        }
        
        /* Era Sections */
        .era-section {
            margin: 3rem 0;
            position: relative;
        }
        
        .era-title {
            font-weight: 700;
            font-size: 1.5rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--primary-color);
        }
        
        .era-description {
            margin-bottom: 1.5rem;
            line-height: 1.7;
        }
        
        /* Filter Controls */
        .filter-controls {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin-bottom: 2rem;
            padding: 1rem;
            background-color: var(--light-gray);
            border-radius: 8px;
        }
        
        .filter-btn {
            background-color: white;
            border: 1px solid var(--border-color);
            border-radius: 20px;
            padding: 0.5rem 1rem;
            cursor: pointer;
            transition: all 0.3s;
            font-size: 0.9rem;
        }
        
        .filter-btn.active {
            background-color: var(--primary-color);
            color: white;
            border-color: var(--primary-color);
        }
        
        .search-container {
            margin-bottom: 2rem;
        }
        
        /* Mathematical Concepts */
        .concept-card {
            background: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-bottom: 1.5rem;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }
        
        .concept-title {
            font-weight: 600;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
        }
        
        .concept-description {
            color: var(--text-muted);
        }
        
        /* Key Figures */
        .figure-card {
            display: flex;
            background: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-bottom: 1.5rem;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }
        
        .figure-image {
            width: 80px;
            height: 80px;
            border-radius: 50%;
            background-color: var(--light-gray);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-right: 1.5rem;
            flex-shrink: 0;
            color: var(--primary-color);
            font-size: 2rem;
        }
        
        .figure-info {
            flex: 1;
        }
        
        .figure-name {
            font-weight: 600;
            margin-bottom: 0.25rem;
        }
        
        .figure-dates {
            color: var(--text-muted);
            font-size: 0.9rem;
            margin-bottom: 0.5rem;
        }
        
        .figure-contributions {
            font-size: 0.95rem;
        }
        
        /* Responsive Adjustments */
        @media screen and (max-width: 768px) {
            .timeline::after {
                left: 31px;
            }
            
            .timeline-item {
                width: 100%;
                padding-left: 70px;
                padding-right: 25px;
            }
            
            .timeline-item:nth-child(even) {
                left: 0;
            }
            
            .timeline-item::after {
                left: 21px;
            }
            
            .timeline-item:nth-child(even)::after {
                left: 21px;
            }
        }