feature(style): fix placeholder text legibility for 2x pwd fields

fixes #717
This is a minimal fix, we could be flashier, but this works. I've implemented it on /change_password and /complete_reset_password.

![issue-717](https://cloud.githubusercontent.com/assets/3323249/2745175/2a4f968e-c732-11e3-9992-22d78d54840c.gif)