Install FlatStudio Gtk theme on Ubuntu 12.10/12.04/11.10/Linux Mint

Install FlatStudio theme on Ubuntu 12.10 Quantal/Ubuntu 12.04 Precise/Ubuntu 11.10 Oneiric/Linux Mint (GTK 3)

FlatStudio theme based on Mediterranean-Night theme. This theme is available in four versions: FlatStudio, FlatStudioLight , FlatStudioGray and FlatStudioDark. These themes are compatible with Gtk 3.6 and Gtk3.4/3.2. Also checkout other themes collection.

FlatStudio-Version

FlatStudioDark-Version

FlatStudioGray-Version

FlatStudioLight-Version

Theme tested on Ubuntu 12.10 Quantal with GTK 3.6
Install Nitrux Icons, Also Check Icons Collection
You can use Gnome-tweak-tool or Ubuntu-Tweak to change themes.

To install FlatStudio theme on Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

Terminal Commands:
sudo add-apt-repository ppa:noobslab/themes
sudo apt-get update
sudo apt-get install flatstudio

That's it

Source: FlatStudio