You can set any CSS value the browser understands. We can't possibly document all of CSS - there are existing websites covering how CSS works which you can use as a reference.
Actually i know CSS, this is what I was asking for: the method of putting into that field.... There was no example or documentation of how to enter these values in. It seems i was on the right track, but didnt try it with quotes. Would be worth putting this screenshot in the manual maybe..?
Thank you for the tutorial / example Colludium