body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}
header, footer {
    background-color: #f0f0f0;
    padding: 1em;
    text-align: center;
}
.logo {
    width: 120px;
}
nav a {
    margin: 0 15px;
    text-decoration: none;
    color: #4CAF50;
}
main {
    padding: 2em;
}