Basic example does not display diagram

[Matteo Gioioso]

Hello, I am trying to use this library, but unfortunately not even the basic example seems to work.

This is a repro: https://codesandbox.io/s/react-diagrams-forked-6sm6lz?file=/src/index.js

Not sure what I am doing wrong, just copy pasting from here: https://projectstorm.gitbook.io/react-diagrams/getting-started/using-the-library

[Matteo Gioioso]

Ok, it was matter of styles, but could be nice to add it to the docs.

Cheers