I am working on migrating some standard teamsites from Sharepoint 2010 to O365.
I deployed the PNP Responsive UI to one of the site collections on O365. On the home page of the rootweb (A wiki page at sitePages/Home.aspx) it works great. When viewed from a phone, I get the modified navigation (the hamburgers) and the webparts on the page are stacked one on top of another.
On the subsites home pages I get the modified navigation, but the webparts are not stacked—they display side by side as they do on a PC view. The subsites homepages are all webpart pages (/siteurl/default.aspx).
Is there something I need to do to get the webparts stacked one on top of another on webpart pages?