Drift is an advanced theme for XenForo. It includes the AD Styler which allows your users to edit the theme subjectively. For example, if they prefer a dark background, they would be able to edit that...
@Audentio : Not sure if it's a bug or not, but on my end of the dark version, the .mainWrap is using the original light's background property, so making a white wrapper by default. I had to manaully change the color.
Also, is it possible to prevent the XenForo copyright showing up twice?
So I'd recommend disabling it. People wanted us to update our products to 1.2.3 before I was able (albeit trying) to fix some of these bugs, so that was my short-term fix, just disable the styler for now.