Why not hide posts without actually deleting them, or give a tag of not mod approved? I hate both censorship and deleted threads on interesting topics, but still appreciate the reasoning behind trying to keep approved answers up to a certain standard.
Question comes from https://www.reddit.com/r/AskHistorians/comments/54yk6m/there_was_a_time_when_everyone_smoked_cigarettes/d86kh9y
Not a historian, but Reddit doesn't work like that.
It might not even be possible though the CSS, as it would change the very foundation of how Reddit Works,, but that would not do anything if an user have disabled that subreddits theme.