Fix Talk sidebar overlapping the PDF viewer
Fix Talk sidebar overlapping the PDF viewer

The iframe of the PDF viewer is shown with an absolute position and full
width and height, so it takes the size of the first parent with a
relative or fixed position. That parent was the main content element,
which is also a parent of the sidebar and therefore its size includes
it, so the iframe filled the content and extended behind the sidebar.
To solve that now a relative position is set for #app-content, which is
a sibling of the sidebar and therefore prevents the iframe from
overlapping it.

Signed-off-by: Daniel Calviño Sánchez <bd7629e975cc0e00ea7cda4ab6a120f2ee42ac1b@gmail.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed