Do you know that situation, remembering a video but you just can't find it? yep.
Hope I was not dreaming... wasn't there a video or stream (maybe pen) where Kevin showed off, perhaps just briefly, a refined grid layout for content? A center line for multi-columns and/or pull-out bits were added.
The only thing I found is the one explaining how we can avoid wrapper containers, which isn't it – link for research wanted dead or alive