Modal Flat - Transparent de BobVonBob

I wasn't a big fan of the new built-in color schemes with the Nova UI redesign, so I set out to find my perfect theme. After searching 50 pages of themes and not finding one that fit my every style desire, I decided to do it myself.

Non-transparent version available here!

Those style choices include:
- Being very dark (but not quite black!)
- A clearly visible active tab
- Dimming the titles of inactive tabs
- Fading the frame when Firefox is unfocused
- Automatic dark/light modes
- Slight transparency on the search bar and other popups
- Setting the popup highlight color so it isn't the default bright blue (rarer than you'd expect!)