Custom Colors Not Rendering (Hosted)

Hi! I’m working with this theme as hosted by a university, and I’m having trouble getting my custom colors to render. The background color works, but the text color and header/sidebar background colors don’t seem to apply. I’d go into the code to try to work it out for myself, but I can’t figure out how to do that in the hosted version (if it’s even possible). My coding skills are minimal, but I’m familiar with the basics of CSS and HTML. I’d really prefer not to have to pay for custom work from the blog support here. Here’s a link to our site: https://blogs.cornell.edu/mendlelab/

Thanks!