Please help me finish up my template QUICKLY? Sidebar trouble.

I simply cannot figure out why my right-hand sidebar is not aligning to the bottom of the header, lining up with the index. In firefox, there is a space above it, and in safari it’s all the way on the bottom right. Anyone help me out? My template is a modification of one I found, so I’m fairly familiar with coding since I’ve done the changes myself. With that in mind, however, if you can help, please explain it to me as simply as you can!

Thanks so much in advance, I hope you can help!