:root {
            --primary-color: #ff6b35;
            --secondary-color: #004e98;
            --accent-color: #ffd166;
            --text-dark: #2d3142;
            --text-light: #f8f9fa;
            --bg-light: #ffffff;
            --bg-dark: #1a1a2e;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.7;
            color: var(--text-dark);
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
        }
        .navbar-brand {
            font-weight: 800;
            font-size: 1.8rem;
            color: var(--primary-color) !important;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
        }
        .hero-section {
            background: linear-gradient(rgba(0,78,152,0.8), rgba(255,107,53,0.8)), url('https://via.placeholder.com/1200x600');
            background-size: cover;
            background-position: center;
            color: white;
            padding: 100px 0;
            text-align: center;
        }
        .section-title {
            color: var(--secondary-color);
            border-left: 5px solid var(--primary-color);
            padding-left: 15px;
            margin: 40px 0 20px;
        }
        .content-card {
            background: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            padding: 25px;
            margin-bottom: 30px;
            transition: transform 0.3s ease;
        }
        .content-card:hover {
            transform: translateY(-5px);
        }
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 15px;
        }
        .highlight-text {
            background: linear-gradient(120deg, var(--accent-color) 0%, var(--accent-color) 100%);
            background-repeat: no-repeat;
            background-size: 100% 0.4em;
            background-position: 0 88%;
            font-weight: 700;
        }
        .img-container {
            border-radius: 10px;
            overflow: hidden;
            margin: 20px 0;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        .table-of-contents {
            background: white;
            border-radius: 10px;
            padding: 20px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            margin: 30px 0;
        }
        .toc-list {
            list-style-type: none;
            padding-left: 0;
        }
        .toc-list li {
            margin-bottom: 10px;
            padding-left: 15px;
            border-left: 3px solid transparent;
            transition: all 0.3s ease;
        }
        .toc-list li:hover {
            border-left: 3px solid var(--primary-color);
            padding-left: 20px;
        }
        .toc-list a {
            text-decoration: none;
            color: var(--text-dark);
            display: block;
        }
        .toc-list a:hover {
            color: var(--primary-color);
        }
        footer {
            background: var(--bg-dark);
            color: var(--text-light);
            padding: 40px 0 20px;
            margin-top: 50px;
        }
        .copyright {
            border-top: 1px solid rgba(255,255,255,0.1);
            padding-top: 20px;
            margin-top: 20px;
            text-align: center;
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 60px 0;
            }
            .navbar-brand {
                font-size: 1.5rem;
            }
        }