body {
    font-family: Arial, sans-serif;margin: 0;padding: 0;
}

header, footer {
    background: #333;
    color: #fff;
    padding: 1em;
    text-align: center;

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

nav ul li {
    display: inline-block;
    margin: 0 1em;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
}

main {
    padding: 2em;
}