Download the iG3L Source Code
On this page you can download the package file for iG3L, and do whatever the heck you want with it. This page is actively updated, and a manual on how to mimic the pre-iOS 7 design fully will be coming soon.

iG3L's development is far from over, but you can download the current version, 1.3, below...it'll be out-of-date soon though. :P

Older versions of the iG3L.css file are available below. (v1.1-1.2.9)