Can I make a theme just for myself - no sharing?

I would like to make a lightweight theme to use just for myself. I don’t want to make it available to anyone else, and I don’t want to have to wait for the mods to approve it. I just want to apply my graphic and move along. Is this possible? I am using Personas Plus.

You should be able to do that using the Personas Plus add-on.

I’m using that. It’s just that the only thing I can see to do with that add-on is “Submit Theme,” and I don’t want to submit anything; I just want to apply it to my own screen.

I used to make my own Personas long before they were available on line. You click on the little fox face in the corner of your add-on bar (or wherever you put it) click customize…then add your header and footer, then click apply. It should stay on your screen. Hope this helps.