body {
    font-family: Arial, sans-serif;
}

header, nav, main {
    padding: 1em;
}

header {
    background-color: #f8f8f8;
    border-bottom: 1px solid #ddd;
}

nav ul {
    list-style: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin-right: 10px;
}

h1 {
    font-size: 2em;
}

h2 {
    font-size: 1.5em;
}