PublicDNS: use different name space in CSS.

Intended to address issue #429

I honestly don't know if this is the correct minimal namespace or if
other restyling may be required.

In testing with `duckpan` the "Answer" text is missing from the header, but this seems like a common property of goodie answers.

![screenshot from 2014-05-10 08 48 16](https://cloud.githubusercontent.com/assets/6280000/2934821/1a141f7c-d7dd-11e3-9d49-2249a05bcff5.png)