EASYSOCIAL (how-to): What file do we edit to render the stream in 2 or 3 columns

Hi,
I would like to render our page streams in 1, 2 or 3 columns depending on the media resolution
I would like to build the page stream using a UIKIT grid
Can you point me to which file the Page stream is built in and which file is the stream module (I'll want to do the same here).
My dev team will figure out how to make sure this is conditional to pages if it's all the same file(s)
Thanks
Danny