Pages --- background image fill and hiding nav bar

We’re developing a yes/no app to determine program eligibility which you can view a demo of the app here and see the two issues we’ve run into:

1. Fill Container with Background Image
Container background images only seem to fill a device’s background if there is content present. The only workaround I’ve found to force the background image to fill all device screens (mobile, tablet, AND desktop) is to add a Rich Text component filled with line breaks. This can’t be the only way to accomplish this and I hope I’m missing something. FYI, the image has been sized to 1920x1080.

2. Hide Top Nav Bar
Since the user determines their own navigation based on the yes/no answers on each screen, global navigation isn’t necessary in this app. To create a more immersive experience for the user, we’d like to hide the white top nav across the top where it currently says, “Full Background App.” How can this be accomplished?

I’ve searched the documentation and community forum without any luck, so thank you in advance for any tips and guidance.