clock disappearing while scrolling mobile Safari

[thomasdeater]

Using the js-es6 branch, I had a countdown timer with visible seconds. On all of the iOS devices we tested, the clock would consistently disappear while scrolling. I found that forcing GPU acceleration using rules like this resolved our issue:

.flip-clock-list { -webkit-transform: translateZ(0); -webkit-perspective: 1000; -webkit-backface-visibility: hidden; }