I am very new to Zorin (my version is 18.1).
The menu items in many windows and especially in Librecalc are all the SAME color as the highlighting color, rendering the selected items invisible.
A web search says this is a common problem in dark themes.
I did select a dark theme for LibreOffice. I tried editing the Format-Themes within LCalc no no avail.
ALSO, I can't be sure this is limited to the LCalc application. I may have seen in other apps as well. At this time while I'm running all around to learn what's where, I'm not sure what I have or have not seen!
I will be obliged if anyone can say how to change the theme or the menu items or the highlight color.
Would you be willing to test if this is limited to LibCalc?
I ask because LibrOffice suite notoriously offers very little widget theming support, unlike most all other applications.
When a light or dark theme is applied, it acts on Classes used by the application, based on the properties listed in the .css.
These Classes are set in the GDK by the application.
LibreOffice does not set any but the most basic Window Classes. I do not know why the developer does this; perhaps ease of coding... But it stands apart as an application on this and makes styling the window, especially for usability, difficult.
Thanks for your comment: I poked around and did not find any other applications where the highlighted font is a problem, so it seems to be Libreoffice only. After some poking around, under TOOLS-OPTIONS search for "Theme" there is a place under LIBREOFFICE-APPEARANCE where new themes can be installed, albeit somehow, the list in the drop down is a bit flaky and does not show all the installed options right away!(maybe me again!) After more poking about, the drop down list grew to five. I selected one of the non-dark ones. Although the new theme is way too bright, it is readable.
I will be happy to hear any other comments, but for now I can proceed with what I have.