It's a stroke of genius, yes, that others have had before now. Lime.js did this three years ago (mapping animations to hardware-accelerated CSS). Cocos2Dx-Javascript does this one step better by bridging into actually-native rendering code. Three.js has DOM-with-CSS-transformations. IIRC someone implemented hardware-accelerated CoreAnimation in Cappuccino using CSS transformations. So, not really new. I'm curious to see what new ideas they DO bring.