I just get a blank page. Is it another one of those where they won't let people in certain parts of the world see it? (I think we had another one of those recently.)
They load HTTP content even if you accessed it via https; your browser might block this "mixed content" because of security reasons. At least, mine does.
They don't seem to have any counters listed unless you chain a bunch of DFFs. They list a max prop delay of 2ns for those from CLK to Q, so if chained and running at GHz speeds you'll be counting propagation delays in dozens of cycles. At that point I imagine you'd have to design skew-tolerant logic rather than try to avoid skew entirely.