I was excited to find this, as it's features filled all the needs of a particular project.
Alas, it fails a number of requirements on the code side to be used.
I suggest you consider the following:
optional css loading, and when it does, do so with the enqueue_style function
ensure to only load when on a page which contains the form.
The rendered form has a serious case of divitis, you could remove them all and just style the label, and input fields, though this is subjective.
Works fine, just doesn't stand up yet..