Following along in the tutorials for using Upfront and have

Following along in the tutorials for using Upfront and have run into an issue. I want to change the hover color on my main menu. I tried using the built-in CSS elements within Upfront to change the hover color in main-nav, but when I click Save, it just reverts back to the aqua that was already there. I also tried creating a new style, but that doesn't seem to save, either. I am clearly doing something wrong, but don't understand what that something is... If it matters, this is a WP Multi-site page and I am logged in as Super-Admin.

Screencast: http://screencast-o-matic.com/watch/cohvrffIDv