Siva Flat is a set of 8 flat-design magnificent looking GTK themes that bring a whole new look for your windows.
The set was created by nale12 who recently added some rounded versions of the existing themes that make the optical result even cooler!
Siva themes make extended use of grey-ish colors combined with red text in dialogs for the required contrast, but what is unique about them is the flat-design approach that makes everything look completely flat.
I absolutely loved Siva simplistic design approach and definitely recommend that you should all give it a try and see if it works for you. What is wrong with being flat after all? Abbott says you can still do anything. So does Siva!