{opacity} Property | CSS: Presentation Layer

Standards Based Development

opacity is one of the few properties that can be properly accelerated; 3D transforms are all accelerated and 2D is typically accelerated (some people use the "null" transform trick there), but opacity is accelerated by default because the GPU can manipulate opacity as easily as scale and transform on the layer. Essentially any layer where you want to fade opacity over a css transition/animation, the browser is smart enough to throw it onto the GPU and do the manipulation.