The concept of not influencing the "outside" is kind of broken at the "root of all things". I'm doing it that way:
http://codepen.io/ysor/pen/WpYyXx
Depending on how responsive your app is, you could render it into a different container without changing it.
http://codepen.io/ysor/pen/XMyYVZ
The app just does not care about the outside.
The layout of an app should not depend on external factors. Everything it needs to layout correct should be scoped under its root.