Different style for first post (and posts.index in replies)

[alff0x1f]

I want make different view for first post and I use <!-- IF !posts.index --> <!-- ENDIF !posts.index -->. But problem in replies (in v1.3.0). In replies {posts.index} is not set, so it false. And replies looks like first post. Any ideas how change first post without changing replies?
May be exist some construction like <!-- IF posts.index=0 -->?

Screenshots:

But problem with it: