main {
    display: flex;
    flex-direction: column;
    align-items: center;
}
main > h1 {
    text-align: center;
    font-size: 5em;
    margin: 1.5% 0 2% 0;
}

#PDFOn {
    width: 80%;
    height: 38em;
}
#PDFOff {
    font-size: 2.5em;
    text-align: center;
}