Python's f-string doesn't have CSS selector

print(f"Some text {x}")
Change the color of this one letter?

The problem is that I don’t see a way to isolate the f-string marker. It’s all treated as one quote.

I found out that you can duplicate one of these rules and change the regular expression to match /\(f"[^"]+"\)/ then assign a special CSS rule. But I don’t know how to do that.