180733 2017-12-12 18:52:38 -0800 Specific CSS styles thrashing the CPU 2017-12-14 01:58:30 -0800 1 1 1 Unclassified WebKit CSS Safari 11 Unspecified Unspecified RESOLVED DUPLICATE 179982 P2 Normal --- 1 malendariel webkit-unassigned bfulgham koivisto simon.fraser zalan oldest_to_newest 1381013 0 malendariel 2017-12-12 18:52:38 -0800 Reduced test case here: https://codepen.io/seancurtis/pen/ypLwwq Changing the calc to calc(100vh - 20px) solves it, as does removing things like the transition or position. Might be revealing something more critical though. Does not happen on 10.x. Still happens on tech preview (11.1 at the time of raising this). 1381151 1 simon.fraser 2017-12-13 09:55:59 -0800 Antti, didn't you fix something like this recently? 1381153 2 simon.fraser 2017-12-13 09:57:52 -0800 I was thinking of bug 179982. 1381545 3 koivisto 2017-12-14 01:58:30 -0800 Yes, this looks like 179982. *** This bug has been marked as a duplicate of bug 179982 ***