how to migrate theme from gtk+-2.0 to gtk+-3.0

[sunil agrawal <sunil agrawal00 gmail com>]

In gtk+-2.0, I have created a pixman based theme. This theme will replace stock images and other widgets images which I mentioned in my gtkrc file.
Now I want to migrate to gtk+-3.0. I tried to parse my gtkrc file but it did not work out.
Is there any way to achieve the same theme in gtk+-3.0 ( using css file or using any other method), Please suggest.