Identity - Profile Activity - GuardianWitness Contributions

![screenshot from 2014-07-04 15 35 11](https://cloud.githubusercontent.com/assets/383630/3482993/8e887d9a-0388-11e4-9c05-76122594c33b.png)

Please use the `transition()` mixin, see https://github.com/guardian/guss-css3/blob/master/_css3.scss#L132