* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            line-height: 1.6;
            color: #333;
            background-color: #f5f5f5;
        }

        header {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            padding: 2rem 0;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        }

        nav {
            background-color: #444;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        nav ul {
            list-style: none;
            display: flex;
            flex-wrap: wrap;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0;
        }

        nav ul li {
            position: relative;
        }

        nav ul li a {
            display: block;
            padding: 1rem 1.5rem;
            color: #fff;
            text-decoration: none;
            transition: background-color 0.3s ease;
            font-size: 0.95rem;
        }

        nav ul li a:hover {
            background-color: #666;
        }

        nav ul li.current a {
            background-color: #667eea;
            font-weight: bold;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 2rem 1.5rem;
        }

        h1 {
            color: #fff;
            font-size: 2.5rem;
            text-align: center;
            margin: 0;
            padding: 1rem 1.5rem;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
        }

        article {
            background: #fff;
            padding: 3rem;
            margin-bottom: 2rem;
            border-radius: 8px;
            box-shadow: 0 2px 15px rgba(0,0,0,0.08);
        }

        article h2 {
            color: #667eea;
            font-size: 1.8rem;
            margin-top: 2rem;
            margin-bottom: 1rem;
            padding-bottom: 0.5rem;
            border-bottom: 3px solid #667eea;
        }

        article h3 {
            color: #764ba2;
            font-size: 1.4rem;
            margin-top: 1.5rem;
            margin-bottom: 0.8rem;
        }

        article h4 {
            color: #555;
            font-size: 1.2rem;
            margin-top: 1.2rem;
            margin-bottom: 0.6rem;
        }

        article p {
            margin-bottom: 1.2rem;
            font-size: 1.05rem;
            line-height: 1.8;
        }

        article ul, article ol {
            margin-left: 2rem;
            margin-bottom: 1.2rem;
        }

        article li {
            margin-bottom: 0.5rem;
        }

        article b, article strong {
            color: #444;
        }

        article em, article i {
            color: #666;
        }

        .transition-section {
            background: #fff;
            padding: 2rem 3rem;
            margin-bottom: 2rem;
            border-radius: 8px;
            box-shadow: 0 2px 15px rgba(0,0,0,0.08);
            border-left: 4px solid #667eea;
        }

        .transition-section p {
            font-size: 1.05rem;
            line-height: 1.8;
            margin-bottom: 1rem;
        }

        .links-section {
            background: #fff;
            padding: 3rem;
            border-radius: 8px;
            box-shadow: 0 2px 15px rgba(0,0,0,0.08);
            margin-bottom: 2rem;
        }

        .links-section h2 {
            color: #667eea;
            font-size: 2rem;
            margin-bottom: 2rem;
            text-align: center;
        }

        .links-section h3 {
            color: #764ba2;
            font-size: 1.5rem;
            margin-top: 2rem;
            margin-bottom: 1rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid #e0e0e0;
        }

        .links-section ul {
            list-style: none;
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 0.8rem 2rem;
            margin-bottom: 2rem;
        }

        .links-section ul li {
            position: relative;
            padding-left: 1.2rem;
        }

        .links-section ul li:before {
            content: "→";
            position: absolute;
            left: 0;
            color: #667eea;
            font-weight: bold;
        }

        .links-section ul li a {
            color: #444;
            text-decoration: none;
            transition: color 0.3s ease;
            font-size: 1rem;
        }

        .links-section ul li a:hover {
            color: #667eea;
            text-decoration: underline;
        }

        footer {
            background-color: #2c2c2c;
            color: #ccc;
            padding: 2rem 0;
            margin-top: 3rem;
        }

        footer .container {
            text-align: center;
        }

        footer p {
            margin-bottom: 0.8rem;
            font-size: 0.95rem;
        }

        footer a {
            color: #667eea;
            text-decoration: none;
            margin: 0 0.5rem;
        }

        footer a:hover {
            color: #764ba2;
            text-decoration: underline;
        }

        @media (max-width: 768px) {
            h1 {
                font-size: 1.8rem;
                padding: 1rem;
            }

            nav ul {
                flex-direction: column;
            }

            nav ul li a {
                padding: 0.8rem 1rem;
                border-bottom: 1px solid #555;
            }

            article {
                padding: 1.5rem;
            }

            article h2 {
                font-size: 1.5rem;
            }

            article h3 {
                font-size: 1.2rem;
            }

            .transition-section {
                padding: 1.5rem;
            }

            .links-section {
                padding: 1.5rem;
            }

            .links-section ul {
                grid-template-columns: 1fr;
                gap: 0.6rem;
            }

            .links-section h3 {
                font-size: 1.3rem;
            }
        }

        @media (max-width: 480px) {
            h1 {
                font-size: 1.5rem;
            }

            article {
                padding: 1rem;
            }

            article h2 {
                font-size: 1.3rem;
            }

            article p {
                font-size: 1rem;
            }

            .links-section {
                padding: 1rem;
            }
        }