:root {
            --primary-color: #ff6b35;
            --secondary-color: #1e3a8a;
            --accent-color: #f59e0b;
            --text-color: #1f2937;
            --light-bg: #f8fafc;
        }
        body {
            font-family: 'Segoe UI', system-ui, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            background-color: var(--light-bg);
        }
        .navbar-brand {
            font-weight: 800;
            font-size: 1.8rem;
            color: var(--primary-color) !important;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.1);
        }
        .hero-section {
            background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
            color: white;
            padding: 4rem 0;
            border-radius: 0 0 30px 30px;
            margin-bottom: 3rem;
        }
        .section-title {
            color: var(--secondary-color);
            border-left: 5px solid var(--accent-color);
            padding-left: 1rem;
            margin: 2.5rem 0 1.5rem;
        }
        .content-card {
            background: white;
            border-radius: 15px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.08);
            padding: 2rem;
            margin-bottom: 2rem;
            transition: transform 0.3s ease;
        }
        .content-card:hover {
            transform: translateY(-5px);
        }
        .key-point {
            background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
            border-left: 4px solid var(--accent-color);
            padding: 1.5rem;
            border-radius: 0 10px 10px 0;
            margin: 1.5rem 0;
        }
        .game-feature {
            text-align: center;
            padding: 1.5rem;
            border-radius: 10px;
            background: white;
            box-shadow: 0 3px 10px rgba(0,0,0,0.1);
            transition: all 0.3s ease;
            height: 100%;
        }
        .game-feature:hover {
            transform: scale(1.03);
            box-shadow: 0 5px 15px rgba(0,0,0,0.15);
        }
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        .img-container {
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            margin: 2rem 0;
        }
        .img-container img {
            width: 100%;
            height: auto;
            transition: transform 0.5s ease;
        }
        .img-container:hover img {
            transform: scale(1.03);
        }
        .table-of-contents {
            background: white;
            border-radius: 15px;
            padding: 2rem;
            box-shadow: 0 5px 15px rgba(0,0,0,0.08);
            margin-bottom: 2rem;
        }
        .toc-item {
            padding: 0.5rem 0;
            border-bottom: 1px solid #e5e7eb;
        }
        .toc-item:last-child {
            border-bottom: none;
        }
        .toc-item a {
            color: var(--text-color);
            text-decoration: none;
            transition: color 0.3s ease;
        }
        .toc-item a:hover {
            color: var(--primary-color);
        }
        footer {
            background: var(--secondary-color);
            color: white;
            padding: 3rem 0 2rem;
            margin-top: 4rem;
        }
        .highlight {
            background: linear-gradient(120deg, #fef3c7 0%, transparent 100%);
            padding: 0.2rem 0.5rem;
            border-radius: 4px;
            font-weight: 600;
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 2.5rem 0;
                border-radius: 0 0 20px 20px;
            }
            .content-card {
                padding: 1.5rem;
            }
        }