body {
    font-family: sans-serif;
    margin: 0;
    padding: 0;
    background: #f5f5f5;
}

header, footer {
    background: #222;
    color: white;
    padding: 1em;
    text-align: center;
}

nav a {
    color: #fff;
    margin: 0 10px;
    text-decoration: none;
}

main {
    padding: 2em;
    max-width: 800px;
    margin: auto;
    background: white;
}