appearance afters upgrade to 20.2

I do not really appreciate that the programmer decides to change the look without giving the choice to the user it's really not beautiful it's difficult to reprogram the look I had try everything changes it would be nice to fix the bugs instead i diffuculty in english my language is french... you have a hint to return on look on version 19 i try setting base.css to complicate..... now all is white no good for my eyes is verry bad for me