1) Get the Xposed installer from Download section from Xposedoofficial thread (the latest version is typically available at this link:http://dl.xposed.info/latest.apk)For Kitkat.
2) Lollipop/Marshmallow- Download
Read This -how to use
With this module you can change the color of the navigation bar when the keyboard is open.
Also can change the color of the navigation buttons.
Kitkat,Lollipop and Marshmallow can change the ripple color and alpha.