Rp Tutorials

So I'm using a lovely layout in this journal by lobelia and I'm almost happy with it except that the navigation bar floats down the page when you scroll. I've looked at the code myself as I'm pretty good at fixing minor things if I can recognize where I need to edit, but I really just have no idea what I need to change in order to fix the navigation at the top of the page. Does anyone here know what I need to do to fix that? The original code for this layout is here.