body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #000;
    color: #fff;
    text-align: center;
}
header {
    background: #111;
    padding: 20px;
}
nav ul {
    list-style: none;
    padding: 0;
}
nav ul li {
    display: inline;
    margin: 0 10px;
}
section {
    margin: 40px 0;
}
footer {
    background: #111;
    padding: 10px;
}