A new theme suite called "Arc Theme" offers flat themes with transparent elements for Gtk 3/2 and Gnome. It is compatible with Gnome 3.18/3.16 and GTK 3.18/3.16, it works under most of the desktops environments which uses GTK engines to render the theme, such as Unity, Gnome, Cinnamon, Mate, and so on. This pack offers three versions 'Arc' which is combination of much Light and less dark colors, second is 'Arc Dark' which offers full dark color, and 3rd 'Arc Darker' also had combination of light & dark theme, you can choose theme whatever meet your requirements. This theme is not compatible with Linux Mint because the latest version of Linux Mint 17 based on Ubuntu 14.04 Trusty which uses old GTK version which is not compatible. There is also arc theme available for Firefox. Arc icons looks great with Arc theme and both makes desktop pretty amazing. You can use Unity Tweak Tool, Gnome-tweak-tool.
Available for Ubuntu 16.04 Xenial/15.10 Wily/Linux Mint 18/other related Ubuntu derivatives
To install Arc themes in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
Available for Ubuntu 16.04 Xenial/15.10 Wily/14.04 Trusty/12.04/Linux Mint 18/17/13/and other related Ubuntu derivatives
To install Arc Icons in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
The following repositories for Fedora 23/22 are provided by Theme author
To install Arc themes in Fedora 22 open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
To install Arc themes in Fedora 22 open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal: