body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f4f4f4;
}
header {
    background: #35424a;
    color: white;
    padding: 10px 0;
    text-align: center;
}
main {
    margin: 20px;
}
footer {
    text-align: center;
    margin-top: 20px;
}