Adapta is one of the most popular GTK themes available for Linux — and yet we’ve never written about it.
Not even once.
Material Inspired Theme
The theme is heavily inspired by Google’s Material Design language. If you’re not a fan of its shadow-heavy look then you probably won’t be a fan of this theme either.
Adapta is an open-source theme and is available in two distinct versions (similar to Arc and Arc Darker): regular Adapta and a half-dark/half-light Adapta-Nokto variant.
If you’re going to be using this theme with the Unity desktop you don’t need to worry about which you use as they look identical. You will notice a difference in Cinnamon, GNOME Shell or Budgie.
Which brings me onto a really awesome point: Adapta works just dandy with pretty much every modern desktop environment, including Unity 7, GNOME Shell, Budgie and Cinnamon.
Install Adapta GTK Theme on Ubuntu
To install the Adapta GTK theme on Ubuntu 16.04 LTS or Ubuntu 16.10 run the following commands in a new Terminal window:
sudo apt-add-repository ppa:tista/adapta
sudo apt-get update && sudo apt-get install adapta-gtk-theme
To change GTK theme on Ubuntu you need to use a utility like Unity Tweak Tool, which is available to install for free from the Ubuntu Software app.