Stuck on CSS stylesheet

Hello,

I’m stuck trying to figure out what someone did to my new theme’s css style sheet. The h1, h2, h3 are not assigned correctly and the font family and font size for the content text and header text seems to be connected when they shouldn’t be. I’m not skilled in css, I’ve been trying to figure it out on my own and changed what seems to be the logical thing based on what I’ve been able to read, but the change would have no affect or a drastic affect. I know it’s a simple change (literally) for someone that knows about this.

Can someone guide me the way if I show you what I’m working with?

I would GREATLY appreciate it.

Pulling my hair out,
T-