If you figure out a way to change the color of table gridlines you would be a hero! These dark themes are great until you open a watch window or something that defaults to a table editor rather than text.
Hello there, are we talking about these gridlines?
Unfortunately I don’t know if it’s possible. Some parts of Automation Studio still have the old architecture that was not built with the theme concept in mind. Thus, there are no hooks to change the colors of every single frame. Our colleagues wrote the items that we can change on GitHub.