Okay idk if anyone can help with this

For a while, my whole view of this site was different, the background was completely white and all my favourites were on the home page, there was this cool thing where you could have a video open on the same page, you could edit the tab and save it as your own, lots of cool stuff.

I clicked on a link on a thread in the pit, might have been a couple of months back, but I switched back using a link at the bottom and now I can't work out how to get it back

Does anyone know how I can get that version back?