I am very glad you asked about this... because in following up, I realized that several of my own themes had this same issue (I don't normally use Evince). Sorry, to take so long- I was correcting each of them before I forget to and making a note to update each theme for uploading.
So... a workaround you can use:
Create a file named gtk.css and place it into your ~/.config/gtk-3.0/ directory
Paste into it: @define-color theme_selected_bg_color #00c3ff;
You can change that color to any color you want. Just ensure that the text color still shows.
Log out and in again to view the change OR just use the theme changer to change the theme to something else, then back again.
Keep an eye on your coming updates: When ZorinGroup releases a theme update, you may want to comment out that line in your ~/.config/gtk-3.0/gtk.css file.