This is what I can see in a cell of an ipynb file:
In Visual studio Code, the text colour has been changed and I don't know why. Before it was white on a black background, and now it is black on a black background, so I can't see anything at all. I know this is not a programming question, but I'm asking because I have no idea how to fix it. Changing the theme colour I manage to fix it, but then the change is not saved.
I need the change to stay permanently for the next time I open VSC.

you can easy access to theme-color by press crtl+shift+p and after that write "color theme" on command pallet section and change the whole theme of the vs. after this every time you open the vscode you can see the chosen theme. make sure you vs code version is the last one.