:root {
            --primary-color: #dc3545;
            --secondary-color: #ffc107;
            --accent-color: #198754;
            --dark-color: #212529;
            --light-color: #f8f9fa;
        }
        body {
            font-family: 'Segoe UI', system-ui, sans-serif;
            line-height: 1.7;
            color: #333;
            background-color: #fff;
        }
        .logo-text {
            font-family: 'Georgia', serif;
            font-weight: bold;
            color: var(--primary-color);
            text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
            font-size: 1.8rem;
        }
        .nav-link {
            font-weight: 500;
            transition: all 0.3s ease;
        }
        .nav-link:hover {
            color: var(--primary-color) !important;
            transform: translateY(-2px);
        }
        .hero-section {
            background: linear-gradient(135deg, var(--primary-color), #c82333);
            color: white;
            padding: 4rem 0;
            margin-bottom: 3rem;
            border-radius: 0 0 20px 20px;
        }
        .section-title {
            color: var(--primary-color);
            border-left: 5px solid var(--secondary-color);
            padding-left: 15px;
            margin: 2.5rem 0 1.5rem;
        }
        .content-card {
            background: white;
            border-radius: 12px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.08);
            padding: 2rem;
            margin-bottom: 2rem;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            border: 1px solid rgba(0,0,0,0.05);
        }
        .content-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px rgba(0,0,0,0.12);
        }
        .highlight-box {
            background: linear-gradient(to right, #fff9e6, #fff3cd);
            border-left: 4px solid var(--secondary-color);
            padding: 1.5rem;
            margin: 1.5rem 0;
            border-radius: 0 8px 8px 0;
        }
        .key-point {
            background-color: var(--light-color);
            padding: 1rem 1.5rem;
            border-radius: 8px;
            margin: 1rem 0;
            border-left: 4px solid var(--accent-color);
        }
        .game-rules {
            background-color: #e8f5e9;
            padding: 1.5rem;
            border-radius: 10px;
            margin: 1.5rem 0;
        }
        .strategy-tip {
            background-color: #e3f2fd;
            padding: 1.5rem;
            border-radius: 10px;
            margin: 1.5rem 0;
            border-left: 4px solid #2196f3;
        }
        img {
            max-width: 100%;
            height: auto;
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
            margin: 1.5rem 0;
        }
        .img-caption {
            text-align: center;
            font-style: italic;
            color: #666;
            margin-top: 0.5rem;
            font-size: 0.9rem;
        }
        footer {
            background-color: var(--dark-color);
            color: white;
            padding: 3rem 0 2rem;
            margin-top: 4rem;
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            background: var(--primary-color);
            color: white;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            text-decoration: none;
            box-shadow: 0 4px 10px rgba(0,0,0,0.2);
            transition: all 0.3s ease;
            z-index: 1000;
        }
        .back-to-top:hover {
            background: #c82333;
            transform: translateY(-3px);
            color: white;
        }
        .table-of-contents {
            background-color: #f8f9fa;
            border-radius: 10px;
            padding: 1.5rem;
            margin: 2rem 0;
        }
        .toc-list {
            list-style-type: none;
            padding-left: 0;
        }
        .toc-list li {
            margin-bottom: 0.8rem;
            padding-left: 1.5rem;
            position: relative;
        }
        .toc-list li:before {
            content: "▶";
            position: absolute;
            left: 0;
            color: var(--primary-color);
        }
        .toc-list a {
            text-decoration: none;
            color: #333;
            transition: color 0.3s ease;
        }
        .toc-list a:hover {
            color: var(--primary-color);
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 2.5rem 0;
            }
            .content-card {
                padding: 1.5rem;
            }
            .section-title {
                font-size: 1.5rem;
            }
        }