Pretty sure the Facebook one is just checking their logged-out page, which is much more straightforward than the logged-in view. Logged-in I count ~144kb of CSS

Pretty sure the Facebook one is just checking their logged-out page, which is much more straightforward than the logged-in view. Logged-in I count ~144kb of CSS, which still isn't bad, but isn't as mind-bogglingly low. Amazon is definitely impressive though! (As are Stripe, Apple, and Airbnb, in basically that order.)