Litmos and Storyline - course player

I'm working with Litmos as an LMS and they have a built-in Content Player. Our users are often confused about the competing navigation. In Litmos I have the ability to hide the "Next Module" button at the top, but then it forces them to "exit" and return to a different page in order to resume. There's also the ability to add custom CSS to the site, but I don't know how to include conditions in the code that would hide the button until the user got to the end of the Storyline content and then reveal it. If anyone has solved this problem, either by custom code in the Litmos player or figuring out how to link the modules together using execute javascript in Storyline, I'd love to know how.