Tweak error message styles

Applies to https://github.com/GigaOM/legacy-pro/issues/4350

Looks like this ( applied to https://research.gostage.it/subscription/sign-up/ )

![screen shot 2014-10-15 at 2 25 38 pm](https://cloud.githubusercontent.com/assets/929375/4651033/c6af2500-5498-11e4-9798-22360403c215.png)


Made the fields overlap and tweaked the margin on the bottom ones to line them up with the top ones.