Find the specific part of code used to draw a background line

I’m trying to edit the Creative Common’s released Paradigm Shift HTML5 Template.

Basically, I’m trying to edit the color of these darker lines in the background.

Yet I can’t find the proper description in the css and, when I visualize it with Chrome Inspector, I can’t find the related stylesheet part.
Is there a better method?
Thanks

>Solution :

Look at #wrapper::before. It has an inline background svg image defined in the background-image rule. See main.css:3224.