Oh no, it's that box-shadow bug again :-(

We fixed in in Firefox 47, but the fix was deemed too risky to be uplifted to Firefox 46. That was probably a mistake. Anyway, Firefox 47 is going to be released in two weeks on June 7th. In the meantime you can remove the box-shadow from .widewrapper.main using the devtools, or you can use Firefox Beta (47) or Firefox Developer Edition (48), which you can get here: https://www.mozilla.org/en-US/firefox/channel/#developer

Great! Thank you for the info! I'll stay with the current version: I have a Chrome installation for exactly that purpose.

It's because of this bug in Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1250947

Disable the box-shadow on .widewrapper.main and it works fine.

Thank you my friend, I just fixed it <3

Thanks!

I noticed that too. But it renders and scrolls perfectly on Chrome. I wonder what's the difference? Firefox is typically a lot slower than Chrome, but the performance difference this time is amazingly large.

It seems to be a bug. See here: https://news.ycombinator.com/item?id=11749503

For me as well. It becomes unresponsive so I can't even debug why it's so slow.

Was bad in Firefox on Windows too (even to the point of me googling to find tab profiling tools for firefox out of curiosity, didn't find anything useful that's still active, so I've no clue what it is doing it)

See this comment here: https://news.ycombinator.com/item?id=11749503

Sorry about that, you can use Reader View in FF which works fine. Crazy part - it's not JS, I tried disabling it and it's still sluggish.

styles-bluegreen.css seems to be the problem, firefox preforms fine if you block it.