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

        body {
            font-family: Arial, Helvetica, sans-serif;
            line-height: 1.6;
            color: #333;
            background-color: #f5f5f5;
        }

        .header-outer {
            background-color: #fff;
            padding: 20px 0;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        .header-inner {
            max-width: 900px;
            margin: 0 auto;
            padding: 0 20px;
            text-align: center;
        }

        .navbar {
            background-color: #2c3e50;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        .navbar-inner {
            max-width: 900px;
            margin: 0 auto;
            padding: 0 20px;
        }

        .navbar ul {
            list-style: none;
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
        }

        .navbar li {
            margin: 0;
        }

        .navbar a {
            display: block;
            padding: 15px 20px;
            color: #fff;
            text-decoration: none;
            transition: background-color 0.3s;
        }

        .navbar a:hover {
            background-color: #34495e;
        }

        .navbar li.selected a {
            background-color: #1a252f;
        }

        .content-wrapper {
            max-width: 900px;
            margin: 30px auto;
            padding: 0 20px;
        }

        h1 {
            color: #2c3e50;
            font-size: 2.5em;
            margin-bottom: 25px;
            padding-bottom: 15px;
            border-bottom: 3px solid #3498db;
        }

        article {
            background-color: #fff;
            padding: 30px;
            margin-bottom: 30px;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        article h2 {
            color: #2c3e50;
            margin-top: 25px;
            margin-bottom: 15px;
            font-size: 1.8em;
        }

        article h3 {
            color: #34495e;
            margin-top: 20px;
            margin-bottom: 12px;
            font-size: 1.4em;
        }

        article h4 {
            color: #34495e;
            margin-top: 15px;
            margin-bottom: 10px;
            font-size: 1.2em;
        }

        article p {
            margin-bottom: 15px;
            text-align: justify;
        }

        article ul, article ol {
            margin-left: 30px;
            margin-bottom: 15px;
        }

        article li {
            margin-bottom: 8px;
        }

        .transition-section {
            background-color: #fff;
            padding: 30px;
            margin-bottom: 30px;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        .transition-section p {
            margin-bottom: 15px;
        }

        .links-section {
            background-color: #fff;
            padding: 30px;
            margin-bottom: 30px;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        .links-section h2 {
            color: #2c3e50;
            margin-bottom: 20px;
            font-size: 2em;
        }

        .links-section h3 {
            color: #34495e;
            margin-top: 25px;
            margin-bottom: 15px;
            font-size: 1.5em;
            border-bottom: 2px solid #ecf0f1;
            padding-bottom: 10px;
        }

        .links-section ul {
            list-style: none;
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 10px 20px;
            margin-bottom: 20px;
        }

        .links-section li {
            margin: 0;
        }

        .links-section a {
            color: #3498db;
            text-decoration: none;
            transition: color 0.3s;
            display: inline-block;
            padding: 5px 0;
        }

        .links-section a:hover {
            color: #2980b9;
            text-decoration: underline;
        }

        .footer-outer {
            background-color: #2c3e50;
            color: #ecf0f1;
            padding: 30px 20px;
            margin-top: 50px;
        }

        .footer-inner {
            max-width: 900px;
            margin: 0 auto;
            text-align: center;
        }

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

            .navbar ul {
                flex-direction: column;
            }

            .navbar li {
                width: 100%;
                border-bottom: 1px solid #34495e;
            }

            .navbar a {
                padding: 12px 15px;
            }

            article {
                padding: 20px;
            }

            article h2 {
                font-size: 1.5em;
            }

            article h3 {
                font-size: 1.3em;
            }

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

            .transition-section {
                padding: 20px;
            }

            .links-section {
                padding: 20px;
            }
        }

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

            article {
                padding: 15px;
            }

            .content-wrapper {
                margin: 15px auto;
            }
        }