Yaru-light and Yaru-dark based on ‘Yaru theme (Ubuntu community theme)’ https://github.com/ubuntu/yaru powered by the community on the Ubuntu hub. Yaru theme design for GTK 3, GTK 2 and Gnome-Shell. Some of the additional tweaks:
Switch gtk control with round radius.
Just unzip the file and place it in your themes directory i.e. ~/.themes/or /usr/share/themes/
I designed this theme get inspired by flat theme style and OSX Yosemite and I made this theme based on Ultra-Flat theme.
**This theme is currently only for Unity and tested on Ubuntu 14.10 with gtk2/xfce/mate support planned for a future release.
Just unzip the file and place it in your themes directory /usr/share/themes