Hi.

If you used medias provided by default, unfortunately there's no way to delete them.
If you don't have time for removing styles for each element, you can use Export to folder then, with Notepad++ (not Notepad by Windows) or other editor do replace in all *.css files of

@media only screen
to
@media only print

This will remove the "media" styles.

Otherwise, use Styles->Code tab on the right to quickly see for each element whether it has media styles applied.