Not sure if doable, but try to integrate personas into the addon!

[bogas04]

It'll be so cool to have Firefox Lightweight Themes (Personas) inside the doorhanger lol. Do investigate the possibility !

[mbad0la]

@bogas04 can you elaborate on this idea?

[bogas04]

The UI that your addon lives in is called a door hanger. It is used throughout the UI, for e.g. in Downloads popup, the site indicator popup etc.

Personas are themes that can be installed in Firefox without requiring to restart. They usually just add a wallpaper to the background of tab-bar. (Note the pink fractal design, that's a persona).

Idea is that the addon extends that wallpaper of the themes inside the popup itself.