You could place them in a table, in which you use a template with two rows, one for the text you are replying to and another for your reply, and choose the background, fonts, etc for each.Oh I see, when I make the post I should put my text in a table. But I'm trying to do this with CSS without having to change how I post things. Stylus only changes styling of existing tags, it does not insert or delete tags themselves, so I was hoping to use Stylus and CSS.
Sorry: I do not really "speak" hypertext and was providing some work arounds.