Love the concept and how you guys are doing it. My first impression is that I don't think the contributor cards should be the dominant element on the landing page, it's tertiary info compared to the library on the left nav. I didn't notice the left nav until scrolling down the page and back up, but that's my favorite part and kind of the meat and potatoes of what you're doing. Maybe you can find a way to highlight that nav bar on the landing page, and slide it to the left where it is now as you get to the content pages.
Thanks for the feedback! Really like your suggestion and agree that it would be better to highlight the categories more.