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

        body {
            font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
            line-height: 1.6;
            color: #444;
            background-color: #fafafa;
        }

        header {
            background-color: #fff;
            border-bottom: 1px solid #e5e5e5;
            padding: 1.5rem 0;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        h1 {
            font-size: 2.5rem;
            color: #444;
            margin-bottom: 0.5rem;
            font-weight: 600;
            text-align: center;
        }

        nav {
            background-color: #fff;
            border-bottom: 1px solid #e5e5e5;
            padding: 1rem 0;
            position: sticky;
            top: 0;
            z-index: 100;
        }

        nav ul {
            list-style: none;
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1.5rem;
        }

        nav a {
            color: #555;
            text-decoration: none;
            font-size: 0.95rem;
            font-weight: 500;
            transition: color 0.3s ease;
            padding: 0.5rem 0;
        }

        nav a:hover {
            color: #529ecc;
        }

        main {
            background-color: #fff;
            max-width: 900px;
            margin: 2rem auto;
            padding: 3rem 2.5rem;
            box-shadow: 0 1px 3px rgba(0,0,0,0.1);
            border-radius: 3px;
        }

        article {
            margin-bottom: 3rem;
        }

        article h2 {
            font-size: 1.8rem;
            color: #444;
            margin: 2rem 0 1rem;
            font-weight: 600;
        }

        article h3 {
            font-size: 1.4rem;
            color: #555;
            margin: 1.5rem 0 0.8rem;
            font-weight: 600;
        }

        article h4 {
            font-size: 1.2rem;
            color: #555;
            margin: 1.2rem 0 0.6rem;
            font-weight: 600;
        }

        article p {
            margin-bottom: 1.2rem;
            color: #555;
            font-size: 1rem;
            line-height: 1.8;
        }

        article ul, article ol {
            margin: 1rem 0 1.5rem 2rem;
            color: #555;
        }

        article li {
            margin-bottom: 0.5rem;
            line-height: 1.7;
        }

        .transition-section {
            margin: 2.5rem 0;
            padding: 2rem 0;
            border-top: 1px solid #e5e5e5;
        }

        .transition-section p {
            color: #555;
            font-size: 1rem;
            line-height: 1.8;
            margin-bottom: 1.2rem;
        }

        .links-section {
            background-color: #f9f9f9;
            padding: 2.5rem;
            border-radius: 3px;
            border: 1px solid #e5e5e5;
            margin-top: 2rem;
        }

        .links-section h3 {
            font-size: 1.3rem;
            color: #444;
            margin: 2rem 0 1rem;
            font-weight: 600;
        }

        .links-section h3:first-child {
            margin-top: 0;
        }

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

        .links-section li {
            margin: 0;
        }

        .links-section a {
            color: #529ecc;
            text-decoration: none;
            font-size: 0.95rem;
            line-height: 1.6;
            display: inline-block;
            transition: color 0.3s ease;
        }

        .links-section a:hover {
            color: #3d7ea6;
            text-decoration: underline;
        }

        footer {
            background-color: #fff;
            border-top: 1px solid #e5e5e5;
            padding: 2rem 0;
            margin-top: 3rem;
            text-align: center;
        }

        footer p {
            color: #999;
            font-size: 0.85rem;
        }

        @media (max-width: 768px) {
            h1 {
                font-size: 2rem;
            }

            nav ul {
                flex-direction: column;
                align-items: center;
                gap: 0.8rem;
            }

            main {
                margin: 1rem;
                padding: 2rem 1.5rem;
            }

            article h2 {
                font-size: 1.5rem;
            }

            article h3 {
                font-size: 1.25rem;
            }

            .links-section {
                padding: 1.5rem;
            }

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

        @media (max-width: 480px) {
            h1 {
                font-size: 1.6rem;
            }

            main {
                padding: 1.5rem 1rem;
            }

            article p, .transition-section p {
                font-size: 0.95rem;
            }
        }