On http://desandro.github.io/3dtransforms/examples/cube-01-steps.html, the elements that form the sides of the cube are listed in order 1, 2, 3, 4, 5, 6 in the HTML source. Steps to reproduce: Load http://desandro.github.io/3dtransforms/examples/cube-01-steps.html Press 2. Rotate faces Expected: Face 2 is z sorted in front of 1 after transition ends Actual: Face 1 is z sorted in front of 2 Discussion: We believe the bug is due to Safari not preserving painter's algorithm order of coplanar layers.