Thank you for your efforts with this nice extension. I am using it every day.
I found at least one site where the extension's adjustment of text contrast makes things worse though. https://www.torontopearson.com/en/flights/schedules/ The text "departures", "arrivals" etc are originally light coloured on dark background, but the extension makes the text colour dark and practically invisible. Maybe you can have a look at that specific case and improve your code?
Thanks again.
Vladimir