Changing Coursepress header background color

I have coursepress them running here:

I've used the following in style.css to edit header background color:
background: #f07d18
border-bottom: 1px solid #c9ced2;
padding: 50px 0px 10px 0px;

It's such a simple tweak, I'm just not sure what's not working. I must be calling the wrong element or something. I have the logo in place, which is transparent, so we need a colored background to make it show up well. But the Customizer only seems to be able to edit the entire background of the whole site.

We need to edit just the background color of the header only. The change I mentioned above seems to have no effect. I've tried clearing my cache. Any insight into what I'm missing is much appreciated.