h2 {
    text-align: center;
}
iframe {
    margin-left: 50px;
    margin-right: 50px;
}
form {
    width: 600px;
    margin-left: auto;
    margin-right: auto;
}
form hr {
    margin-top: 2em;
    margin-bottom: 2em;
}
form h3 {
    margin-top: 3em;
}