I have a SharePoint 2013 publishing site with a relatively highly customized master page. This master page is in use for both the system master page and the default master page. Problem: it causes the date picker on web-browsable InfoPath forms to be unstyled. I switch back to seattle.master and it works as expected.
How can I fix this on my master page? It's pretty thoroughly customized but the basics all seem to be there, when compared against seattle.master. Is there some specific CSS file I can call up on the system master page to get the date picker to show up? I don't care if this has to be manual I just need it to work.