Allow Sections to be collapsable to help with page organization

In my files I have some core mobile designs, and then I usually have a section that points out changes when it gets to tablet size. Or, there could be sections that have background information in them that isn’t needed to view all the time. It would be nice to be able to collapse/expand sections so that upon first view of a page it’s not super cluttered. And then, should you need to expand the sections, you can