body {
    font-family: Arial, sans-serif;
    background: #111;
    color: #fff;
    margin: 0;
    padding: 0;
}
header {
    background: #222;
    padding: 1em;
    text-align: center;
}
nav a {
    color: yellow;
    margin: 0 10px;
    text-decoration: none;
}
main {
    padding: 2em;
}
footer {
    background: #222;
    text-align: center;
    padding: 1em;
    position: fixed;
    bottom: 0;
    width: 100%;
}