How to optimize css3 animation on older devices?

Question

css

Tell me how you optimize CSS3 animation for older mobile devices.
The effects of the exit menu are terribly slow

.quest-aside
  position: fixed
  top: 87px
  bottom: 0
  width: 310px
  left: -310px
  z-index: 10001
  background-position: center -89px
  +transition-property(left)
  +transition-duration(1s)
  overflow: auto
  &.active
    left: 0

Answer 1

no need to animate positioning, animate via transform translate

Answer 2

No need to animate anything in older browsers. There effects should be simple, on/off. No intermediate animations. Everything slows down for people anyway, ancient computers can hardly pull modern sites, and then there’s animation. Nail in the coffin.

Answer 3

animate via transform translate