body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}
header {
    background-color: #333;
    color: #fff;
    padding: 10px 0;
    text-align: center;
}
nav {
    background-color: #444;
    overflow: hidden;
}
nav a {
    display: block;
    color: #fff;
    text-align: center;
    padding: 14px 20px;
    text-decoration: none;
    float: left;
}
nav a:hover {
    background-color: #ddd;
    color: black;
}
.content {
    padding: 20px;
}