I like this, but with one exception: Change the background color towards white instead of the username towards green. Adding more contrast with the background

I like this, but with one exception: Change the background color towards white instead of the username towards green. Adding more contrast with the background helps pick out the good/important comments, when skimming, and is consistent with the semantics of text color fading. Although it would be even more consistent if the text color transitioned to something, I think it would look worse. An additional option would be to adjust text color by downvotes and background by upvotes - this would also highlight controversial posts, which may or may not be desirable.