GeneratePress with NinjaForms doesn't seem to use the GP css

Hello GP,

According to NinjaForms' website:
How Ninja Forms Handles Styling
The thing to note here is that Ninja Forms adds very little styling of its own by default. Instead we inherit the styling of your theme, the design layer of your WordPress website. What this means is that if your theme adds basic default styling to all html form elements, Ninja Forms will look just as your theme author intended. If your theme does not style theme elements or makes strange opinionated decisions, Ninja Form will inherit those as well.

I created a simple page and added a single shortcode pointing to the ninja form, but the Submit button is black and should be blue according to my GP Colors. Any idea why?

Login is first part of the site domain before wpengine.com
Pw : 725de60a

Thanks!

Alex