:root {
            --primary-color: #ff6b35;
            --secondary-color: #1a237e;
            --accent-color: #ffd54f;
            --text-color: #333333;
            --light-bg: #f8f9fa;
        }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        }
        .main-container {
            background: white;
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.2);
            margin-top: 20px;
            margin-bottom: 20px;
            overflow: hidden;
        }
        .logo-header {
            background: linear-gradient(45deg, var(--secondary-color), var(--primary-color));
            color: white;
            padding: 2rem 0;
            text-align: center;
            border-bottom: 5px solid var(--accent-color);
        }
        .logo-text {
            font-size: 3.5rem;
            font-weight: 800;
            text-shadow: 3px 3px 0 rgba(0,0,0,0.2);
            letter-spacing: 2px;
        }
        .nav-custom {
            background: var(--secondary-color) !important;
            border-bottom: 3px solid var(--accent-color);
        }
        .nav-custom .nav-link {
            color: white !important;
            font-weight: 600;
            padding: 1rem 1.5rem;
            transition: all 0.3s ease;
        }
        .nav-custom .nav-link:hover {
            background: var(--primary-color);
            transform: translateY(-2px);
        }
        .content-section {
            padding: 3rem 2rem;
        }
        h1, h2, h3 {
            color: var(--secondary-color);
            margin-bottom: 1.5rem;
            font-weight: 700;
        }
        h1 {
            border-bottom: 3px solid var(--primary-color);
            padding-bottom: 0.5rem;
            font-size: 2.5rem;
        }
        h2 {
            border-left: 5px solid var(--accent-color);
            padding-left: 1rem;
            margin-top: 2.5rem;
            font-size: 2rem;
        }
        h3 {
            color: var(--primary-color);
            font-size: 1.5rem;
            margin-top: 2rem;
        }
        p {
            margin-bottom: 1.5rem;
            text-align: justify;
            font-size: 1.1rem;
        }
        .key-point {
            background: var(--light-bg);
            border-left: 4px solid var(--primary-color);
            padding: 1.5rem;
            margin: 1.5rem 0;
            border-radius: 0 8px 8px 0;
        }
        .feature-icon {
            color: var(--primary-color);
            margin-right: 10px;
            font-size: 1.2rem;
        }
        .image-container {
            text-align: center;
            margin: 2.5rem 0;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        .image-container img {
            max-width: 100%;
            height: auto;
            transition: transform 0.5s ease;
        }
        .image-container img:hover {
            transform: scale(1.03);
        }
        .caption {
            font-style: italic;
            color: #666;
            margin-top: 0.5rem;
            padding: 0 1rem;
        }
        .highlight {
            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;
            padding: 0 2px;
        }
        .footer {
            background: var(--secondary-color);
            color: white;
            padding: 2rem 0;
            margin-top: 3rem;
            border-top: 5px solid var(--accent-color);
        }
        @media (max-width: 768px) {
            .logo-text {
                font-size: 2.5rem;
            }
            .content-section {
                padding: 2rem 1rem;
            }
            h1 {
                font-size: 2rem;
            }
            h2 {
                font-size: 1.7rem;
            }
            .nav-custom .nav-link {
                padding: 0.8rem 1rem;
            }
        }
        .table-of-contents {
            background: var(--light-bg);
            border-radius: 10px;
            padding: 1.5rem;
            margin: 2rem 0;
            border: 1px solid #e0e0e0;
        }
        .toc-heading {
            color: var(--primary-color);
            border-bottom: 2px solid var(--primary-color);
            padding-bottom: 0.5rem;
            margin-bottom: 1rem;
        }
        .toc-list {
            list-style-type: none;
            padding-left: 0;
        }
        .toc-list li {
            margin-bottom: 0.8rem;
            padding-left: 1rem;
            border-left: 3px solid transparent;
            transition: all 0.3s ease;
        }
        .toc-list li:hover {
            border-left-color: var(--primary-color);
            padding-left: 1.5rem;
        }
        .toc-list a {
            color: var(--text-color);
            text-decoration: none;
            font-weight: 500;
        }
        .toc-list a:hover {
            color: var(--primary-color);
        }