I fiddled around the past couple of days learning the basics of this app and I created a template. Once the template was done, I created a bunch of folders and copied my template into them to begin editing. Once I got into a page that was in a folder, it did not appear to see the CSS file.
After a brief panic, I closed the app and rebooted and all was well. Not sure what happened, but it gave me a good scare, as the header is pretty locked down in the app.
Rebooting the app fixed the problem. I'm memorializing it here in case someone else encounters the same issue.