big style fix

Just [a little bit further down](https://github.com/InGo-LLP/widgets-login/pull/42/files#diff-db89d614e625694a467a3be74d8b2cc9R34) we set everything inside of `.ingo-popup` to `box-sizing: border-box`.  Do we just want to switch to `border-box` for the default reset here and just make sure it doesn't break anything? (Rather than switching two divs down to a totally different box model just because).