Change font in posts

I know this might be a bit silly, but I simply don’t know how to change the font on my site.

Here it is: https://yoke.dk/newsite/

I’ve found where to change the font for the menu and all the headlines (right now set to Arial).

The rest of the text is the problem. Both on the Projects and the About pages. I want this set to Arial as well.

I can see through the Firebug app that the element I’m looking for is:
element.style {
font-family:Calibri;
}

But I can’t find this in my childtheme and I don’t know what the element.style refers too?

How do I do this?

Thanks!
– Jesper