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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            color: #333;
            background-color: #f5f5f5;
        }

        header {
            background: linear-gradient(135deg, #2c5f8d 0%, #4a8fc7 100%);
            color: white;
            padding: 2rem 0;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        }

        header h1 {
            text-align: center;
            font-size: 2.5rem;
            font-weight: 300;
            letter-spacing: 1px;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        nav {
            background-color: #fff;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            position: sticky;
            top: 0;
            z-index: 1000;
        }

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

        nav ul li {
            margin: 0;
        }

        nav ul li a {
            display: block;
            padding: 1rem 1.5rem;
            color: #2c5f8d;
            text-decoration: none;
            font-weight: 500;
            transition: all 0.3s ease;
            border-bottom: 3px solid transparent;
        }

        nav ul li a:hover,
        nav ul li a.selected {
            background-color: #f0f7ff;
            border-bottom-color: #4a8fc7;
            color: #1a4d7a;
        }

        main {
            max-width: 1200px;
            margin: 3rem auto;
            padding: 0 20px;
        }

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

        article h2 {
            color: #2c5f8d;
            margin: 2rem 0 1rem 0;
            font-size: 1.8rem;
            font-weight: 600;
        }

        article h3 {
            color: #2c5f8d;
            margin: 1.5rem 0 0.8rem 0;
            font-size: 1.4rem;
            font-weight: 600;
        }

        article h4 {
            color: #4a8fc7;
            margin: 1.2rem 0 0.6rem 0;
            font-size: 1.2rem;
            font-weight: 600;
        }

        article p {
            margin-bottom: 1.2rem;
            font-size: 1.05rem;
            color: #444;
            text-align: justify;
        }

        article img {
            max-width: 100%;
            height: auto;
            border-radius: 5px;
            margin: 1.5rem 0;
        }

        .transition-section {
            background-color: white;
            padding: 2.5rem 3rem;
            margin-bottom: 3rem;
            border-radius: 8px;
            box-shadow: 0 2px 15px rgba(0,0,0,0.08);
        }

        .transition-section p {
            font-size: 1.05rem;
            color: #444;
            margin-bottom: 1rem;
            line-height: 1.7;
        }

        .links-section {
            background: linear-gradient(to bottom, #ffffff 0%, #f8fbff 100%);
            padding: 3rem;
            border-radius: 8px;
            box-shadow: 0 2px 15px rgba(0,0,0,0.08);
            margin-bottom: 3rem;
        }

        .links-section h2 {
            color: #2c5f8d;
            margin-bottom: 2rem;
            font-size: 2rem;
            text-align: center;
            font-weight: 600;
        }

        .links-section h3 {
            color: #2c5f8d;
            margin: 2rem 0 1rem 0;
            font-size: 1.5rem;
            font-weight: 600;
            border-bottom: 2px solid #e0e0e0;
            padding-bottom: 0.5rem;
        }

        .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: #4a8fc7;
            font-weight: bold;
            font-size: 1.3rem;
        }

        .links-section ul li a {
            color: #2c5f8d;
            text-decoration: none;
            font-size: 1rem;
            transition: all 0.3s ease;
            display: inline-block;
        }

        .links-section ul li a:hover {
            color: #4a8fc7;
            padding-left: 0.5rem;
        }

        footer {
            background: linear-gradient(135deg, #1a4d7a 0%, #2c5f8d 100%);
            color: white;
            padding: 2rem 0;
            margin-top: 4rem;
        }

        footer .footer-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            text-align: center;
        }

        footer p {
            margin: 0.5rem 0;
            font-size: 0.95rem;
            opacity: 0.9;
        }

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

            nav ul {
                flex-direction: column;
            }

            nav ul li {
                width: 100%;
                text-align: center;
                border-bottom: 1px solid #e0e0e0;
            }

            nav ul li:last-child {
                border-bottom: none;
            }

            nav ul li a {
                padding: 0.8rem 1rem;
            }

            article {
                padding: 1.5rem;
            }

            article h2 {
                font-size: 1.5rem;
            }

            article h3 {
                font-size: 1.3rem;
            }

            .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) {
            header h1 {
                font-size: 1.5rem;
            }

            article p,
            .transition-section p {
                text-align: left;
            }
        }