Only show pop up on mobile devices

Hi all,

i am trying to hide the pop up on all devices but mobile devices. I am using the following css to achieve this:

/* Hide the popup by default */ pum-9033 {

display: none !important;

}

/* Show the popup only on mobile devices (max-width: 768px) */
@media only screen and (max-width: 768px) {
#pum-9033 {
display: block !important;
}
}

This works in general but what happens is, that the pop up is hidden but the vertical scroll bar is hidden as well so that the user is stuck and cannot scroll down or up on the page.

is there a better way of doing this?

Thanks a lot in advance!