My facebook login changes every other hour. I thought I’m just having CSS/UI loading delays. But 9:06PM PST I was locked out from my account. Then when I re-login a new index page was shown
Another one earlier has a different CSS and UI. I was not able to screen shot it. But in my opinion they are experimenting the interface for the more recent OS, the Windows 8, which uses Metro and a right scrolling page styling.