Click on any link to show the popup notification.
This animation works on Safari 5.0.5 on Windows... but does not work on Mac. I've also noticed this behavior on iOS.
To make it work, you have to remove the visibility property as part of the transition.
Confused because same Safari ver on Windows works but not on Mac. You can see it working if you try FF4+ or Chrome.
Works on Mac if I disable accelerated compositing.
*** This bug has been marked as a duplicate of bug 29984 ***
I switched humane-js to use z-index instead of visibility so the above link should work now but the issue remains.