Editing font-family – can't find CSS

I’m trying to change the font-family of some heading text; however, I cannot find the CSS for it.

I’ve searched in every .css file I have access to and still can’t find it. When I inspect the heading in Chrome it shows the font-family line of CSS and says it is located in runaroundaroo.com, not style.css or any .css file. How do I access this CSS?