:root {
            --primary-color: #1a5276;
            --secondary-color: #e74c3c;
            --accent-color: #f39c12;
            --text-color: #2c3e50;
            --light-bg: #ecf0f1;
            --dark-bg: #2c3e50;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            background-color: #f8f9fa;
        }
        .navbar-brand {
            font-weight: 800;
            font-size: 1.8rem;
            color: var(--primary-color) !important;
            text-shadow: 1px 1px 3px rgba(0,0,0,0.1);
        }
        .nav-link {
            font-weight: 600;
            transition: all 0.3s ease;
        }
        .nav-link:hover {
            color: var(--secondary-color) !important;
            transform: translateY(-2px);
        }
        .hero-section {
            background: linear-gradient(135deg, var(--primary-color), #2980b9);
            color: white;
            padding: 4rem 0;
            margin-bottom: 2rem;
            border-radius: 0 0 20px 20px;
        }
        h1, h2, h3 {
            color: var(--primary-color);
            margin-bottom: 1.5rem;
        }
        h1 {
            font-size: 2.5rem;
            font-weight: 800;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.1);
        }
        h2 {
            font-size: 2rem;
            border-left: 5px solid var(--accent-color);
            padding-left: 15px;
            margin-top: 2.5rem;
        }
        h3 {
            font-size: 1.5rem;
            color: var(--secondary-color);
            margin-top: 2rem;
        }
        .content-section {
            background: white;
            border-radius: 15px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            padding: 2.5rem;
            margin-bottom: 2rem;
        }
        .highlight-box {
            background-color: var(--light-bg);
            border-left: 4px solid var(--accent-color);
            padding: 1.5rem;
            margin: 1.5rem 0;
            border-radius: 0 8px 8px 0;
        }
        .key-feature {
            background: linear-gradient(135deg, #e3f2fd, #f3e5f5);
            border-radius: 10px;
            padding: 1.5rem;
            margin: 1rem 0;
            transition: transform 0.3s ease;
        }
        .key-feature:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0,0,0,0.1);
        }
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        img {
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            transition: transform 0.3s ease;
            max-width: 100%;
            height: auto;
        }
        img:hover {
            transform: scale(1.02);
        }
        .img-caption {
            font-style: italic;
            text-align: center;
            margin-top: 0.5rem;
            color: #666;
        }
        footer {
            background-color: var(--dark-bg);
            color: white;
            padding: 2rem 0;
            margin-top: 3rem;
        }
        .footer-heading {
            color: var(--accent-color);
            margin-bottom: 1rem;
        }
        .copyright {
            background-color: rgba(0,0,0,0.2);
            padding: 1rem;
            text-align: center;
            margin-top: 2rem;
        }
        .table-of-contents {
            background-color: var(--light-bg);
            border-radius: 10px;
            padding: 1.5rem;
            margin-bottom: 2rem;
        }
        .toc-heading {
            color: var(--primary-color);
            border-bottom: 2px solid var(--accent-color);
            padding-bottom: 0.5rem;
            margin-bottom: 1rem;
        }
        .toc-list {
            list-style-type: none;
            padding-left: 0;
        }
        .toc-list li {
            margin-bottom: 0.5rem;
            padding-left: 1rem;
            border-left: 3px solid transparent;
            transition: all 0.3s ease;
        }
        .toc-list li:hover {
            border-left: 3px solid var(--secondary-color);
            padding-left: 1.5rem;
        }
        .toc-list a {
            text-decoration: none;
            color: var(--text-color);
            transition: color 0.3s ease;
        }
        .toc-list a:hover {
            color: var(--secondary-color);
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 2rem 0;
            }
            h1 {
                font-size: 2rem;
            }
            h2 {
                font-size: 1.7rem;
            }
            .content-section {
                padding: 1.5rem;
            }
        }
        .keyword-highlight {
            font-weight: 700;
            color: var(--primary-color);
            background-color: rgba(26, 82, 118, 0.1);
            padding: 0 5px;
            border-radius: 3px;
        }
        .quote-box {
            border-left: 4px solid var(--secondary-color);
            background-color: #fff5f5;
            padding: 1.5rem;
            margin: 1.5rem 0;
            font-style: italic;
        }
        .stat-number {
            font-size: 2.5rem;
            font-weight: 800;
            color: var(--secondary-color);
            display: block;
        }
        .stat-label {
            font-size: 1rem;
            color: var(--text-color);
        }