Stage 1: CSS on Cohost is used mostly in fun random ways, or in imitation of graphic design conventions external to the social sphere.
Stage 2: CSS is used memetically in imitation of other Cohost posts, but still in a way that references external conventions. Examples include "this user can say it" and The Uxbridge English Dictionary.
Stage 3: CSS begins to be used in ways that are purely referential to Cohost cultural conventions. I have not seen any examples of this yet, but I'm excited for them to start appearing.