Coursepress Pro Formatting Issues on Unit-Page

Sorry the site itsself is in German:
http://www.strebix.de/kurse/die-zelle-basiskurs/lerneinheit/uebersicht-die-zelle/

Here you find "Integrationsebenen" what is actually the Heading for this Unit-Page
see attached file .
I cannot find any class or div information to change the font-size or other chance to change the styling via css.

Can you give me a helping hand?
What template is used. So we can modify it hard coded?
Or is a chance to do it with CSS?

Thank you for your support