A non-transparent version of the theme is available here: Arc Solid OBS repo. Manual Installation.
Getting the latest version of the Arc GTK theme on Ubuntu 16.04 is simple. You have a number of choices available. You can add the theme designer’s personal repository to get new versions of Arc on Ubuntu 16.04 LTS as and when they’re released.
Install Arc Theme on Firefox Ubuntu.
Changes the color of Firefox default theme. Compatible with Australis (Firefox 29) (work in progress).
Der Mozilla Firefox-Browser kann mithilfe von Themes, sogenannten Personas, persönlich angepasst 12 Sep 2013 GNOME 3 Theme Applied to Firefox in Ubuntu GNOME I'm using XFCE with my own transparent holo style layout and theming...
Dust requires murrine 0.91, available in Ubuntu 10.04 (Lucid) and newer. If you are using an older version, try
Add-ons for Firefox. Themes.
Themes for Ubuntu/Linux Mint.
I set out to file several bugs, most of them being against the default Firefox theme included with Ubuntu, which didn't really match any of the desktop's colors or icons.
Re: firefox transparency. That windows transparent firefox was done with glasser.As I said,it's not available for linux.However,if there was a way to get firefox transparent in ubuntu,I could adjust the opacified text with some css editing.