A CodePen by Hugo Giraudel. Smiley hack: WebKit - Both following rules seems to be interpreted only by Chrome:

(;selector: value;);  
[;selector: value;];  

Hacked:  

* Chrome 26: hacked
* Chrome 26: hacked
* Chrome Canary 28: hacked
* Safari 6.0.4: hacked
* Safari 6 iOS: hacked
* Mercury 7.4: hacked

Passed:

* Opera Mini 7: success
* Chrome Canary 29: success
* Firefox 20: success
* Firefox Aurora 23: success
* Internet Explorer 10: success

Any test very much appreciated!