body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.6;
}
header {
    background: #555;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}
header nav a {
    color: #fff;
    margin: 0 15px;
    text-decoration: none;
}
main {
    padding: 1rem;
}
footer {
    text-align: center;
    background: #555;
    color: #fff;
    padding: 1rem 0;
    position: fixed;
    bottom: 0;
    width: 100%;
}