Delete left (white) panel in CSS/HTML?

I am looking now for hours but I can't find the right code line:

In this example/template you see a menu/panel on the left side which I just want to delete. I want to use the home screen centered. It should look like that there was never a panel-menu available.

This ist the html-file:http://ift.tt/1ST48gd

This is the corresponding CSS file: http://ift.tt/1NLB5Mx

I am sure that it is not too complicated but honestly I am quite new to this topic. Your help is really appreciated. Thank you in advance.