Improve the visibility of the link preview popup
from @lilydjwg:
it's not very obvious that a popover is showing (there is only slight gray borders). It'd be better with a more obvious border or different background color.
Version: 40.4-1 (Fedora Workstation 34), Master Flatpak (Date: 2021-09-20 19:06:17 +0000)
Steps to reproduce (to notice it):
- Open a PDF file with a table of contents and set zoom to 'Fit Width'. Test case: Red_Hat_Enterprise_Linux-7-Virtualization_Deployment_and_Administration_Guide-en-US-2.pdf
- Move the mouse on a entry of the table of contents.
- The preview link pop-up shows.
- Notice the pop-up is not very distinguishable from the rest of the entries.
Edited by Michaël Berteaux