Fix container title colour on media page

Fix a tiny regression resulting from https://github.com/guardian/frontend/pull/6585

Broken: 
![screen shot 2014-10-20 at 13 11 42](https://cloud.githubusercontent.com/assets/813383/4700911/8e86189c-5852-11e4-920c-b85b1fd0513c.png)

Fixed:
![screen shot 2014-10-20 at 13 11 52](https://cloud.githubusercontent.com/assets/813383/4700914/93d8945a-5852-11e4-93fa-c10b164d9823.png)