:root {
            --primary-color: #ff6b35;
            --secondary-color: #f7931e;
            --accent-color: #2ecc71;
            --text-dark: #2c3e50;
            --text-light: #7f8c8d;
            --bg-light: #f8f9fa;
        }
        body {
            font-family: 'Segoe UI', system-ui, sans-serif;
            line-height: 1.7;
            color: var(--text-dark);
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        }
        .main-container {
            background: white;
            border-radius: 20px;
            box-shadow: 0 15px 50px rgba(0,0,0,0.1);
            overflow: hidden;
            margin-top: 20px;
            margin-bottom: 20px;
        }
        .logo-header {
            background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
            color: white;
            padding: 30px 0;
            text-align: center;
            position: relative;
            overflow: hidden;
        }
        .logo-header h1 {
            font-size: 3.5rem;
            font-weight: 800;
            text-shadow: 3px 3px 0 rgba(0,0,0,0.2);
            margin: 0;
            letter-spacing: 2px;
        }
        .logo-header .subtitle {
            font-size: 1.2rem;
            opacity: 0.9;
            margin-top: 10px;
        }
        .nav-custom {
            background: var(--text-dark);
            padding: 0;
        }
        .nav-custom .nav-link {
            color: white !important;
            padding: 15px 20px;
            font-weight: 600;
            transition: all 0.3s ease;
            border-bottom: 3px solid transparent;
        }
        .nav-custom .nav-link:hover, 
        .nav-custom .nav-link.active {
            background: rgba(255,255,255,0.1);
            border-bottom: 3px solid var(--primary-color);
        }
        .content-section {
            padding: 40px 30px;
        }
        h2 {
            color: var(--primary-color);
            border-left: 5px solid var(--secondary-color);
            padding-left: 15px;
            margin-top: 40px;
            margin-bottom: 25px;
            font-weight: 700;
        }
        h3 {
            color: var(--secondary-color);
            margin-top: 30px;
            margin-bottom: 15px;
            font-weight: 600;
        }
        .highlight-box {
            background: linear-gradient(135deg, #ffeaa7, #fab1a0);
            border-radius: 10px;
            padding: 25px;
            margin: 25px 0;
            border-left: 5px solid var(--primary-color);
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
        }
        .game-feature {
            background: var(--bg-light);
            border-radius: 10px;
            padding: 20px;
            margin: 15px 0;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            border: 1px solid #e9ecef;
        }
        .game-feature:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px rgba(0,0,0,0.1);
        }
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 15px;
        }
        .img-container {
            border-radius: 10px;
            overflow: hidden;
            margin: 30px 0;
            box-shadow: 0 10px 30px rgba(0,0,0,0.1);
            position: relative;
        }
        .img-container img {
            width: 100%;
            height: auto;
            transition: transform 0.5s ease;
        }
        .img-container:hover img {
            transform: scale(1.03);
        }
        .img-caption {
            background: rgba(0,0,0,0.7);
            color: white;
            padding: 10px 15px;
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
        }
        .key-point {
            background: white;
            border-radius: 8px;
            padding: 15px;
            margin: 10px 0;
            box-shadow: 0 3px 10px rgba(0,0,0,0.05);
            border-left: 4px solid var(--accent-color);
        }
        .key-point i {
            color: var(--accent-color);
            margin-right: 10px;
        }
        footer {
            background: var(--text-dark);
            color: white;
            padding: 40px 0 20px;
            margin-top: 50px;
        }
        .copyright {
            border-top: 1px solid rgba(255,255,255,0.1);
            padding-top: 20px;
            margin-top: 30px;
            text-align: center;
            font-size: 0.9rem;
            opacity: 0.7;
        }
        @media (max-width: 768px) {
            .logo-header h1 {
                font-size: 2.5rem;
            }
            .content-section {
                padding: 25px 20px;
            }
            h2 {
                font-size: 1.8rem;
            }
        }
        .strategy-tip {
            background: linear-gradient(135deg, #a29bfe, #74b9ff);
            color: white;
            border-radius: 10px;
            padding: 20px;
            margin: 20px 0;
        }
        .cultural-note {
            background: linear-gradient(135deg, #fd79a8, #e17055);
            color: white;
            border-radius: 10px;
            padding: 20px;
            margin: 20px 0;
        }
        .keyword-highlight {
            background: linear-gradient(120deg, #a8e6cf, #dcedc1);
            padding: 2px 6px;
            border-radius: 4px;
            font-weight: 600;
        }