Fixed: with the last update I introduced a small bug where the frame would clarify itself when the Chrome window was inactive. This obviously doesn't match my quality, so I already fixed it.
Fixed: now when you install the theme, the text that says that you installed a theme matches the tab text, omnibox text, bookmark text and toolbar icons instead of difficult to see grey. It also affects the sidebar title of things (Customize Chrome, Favorites and others).
Firefox Dark is officially launched in the Chrome Web Store! 🎉