header {
    background-color: grey;
    color: #fff;
    padding: 20px;
    text-align: center;
}
body {
    background-color: #333;
}
nav {
    background-color: #444;
    padding: 10px;
}
nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
}
nav ul li {
    display: inline;
    margin-right: 10px;
}
nav ul li a {
    color: white;
    text-decoration: none;
}
nav ul li a:hover {
    text-decoration: underline;
}
main {
    color: white;
    padding: 20px;
    text-align: center;
}
footer {
    background-color: black;
    color: white;
    text-align: center;
    padding: 10px;
}