Can you see if the CSS is present in .config/joplin-desktop/tmp? (I assume this works the same for Windows here as it does Linux), it won't be under its original name but there shouldn't be many files in there to look through.
Can you see if the CSS is present in .config/joplin-desktop/tmp? (I assume this works the same for Windows here as it does Linux), it won't be under its original name but there shouldn't be many files in there to look through.