/* Reset some default styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    background-color: #f4f4f4;
}

header {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 20px 0;
}

nav ul {
    list-style-type: none;
    display: flex;
    justify-content: center;
}

nav li a {
    color: white;
    margin: 15px;
    font-size: 1.2em;
    text-decoration: none;
}

main section {
    padding: 20px;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

footer {
    text-align: center;
    padding: 20px 0;
    background-color: #333;
    color: white;
}

</footer>

</body>
</html>
```