body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}
header {
    background-color: #0f172a;
    color: white;
    padding: 1em;
}
nav ul {
    list-style-type: none;
    padding: 0;
}
nav ul li {
    display: inline;
    margin-right: 1em;
}
nav ul li a {
    color: white;
    text-decoration: none;
}
main {
    padding: 2em;
}
footer {
    background-color: #e2e8f0;
    padding: 1em;
    text-align: center;
}