Yes!
My post “Add Emojis to folder titles in explorer without renaming folders” shows how to do this with folders.
To select an individual file in the file explorer window, the css selector would be div[data-path="Path/to/file.md"] .nav-file-title-content.
So for instance, div[data-path="Notes/Spec.md"] .nav-file-title-content selects the note called “Spec” in my “Notes” folder in the file explorer.
I hope this helps!