Reduce Lesson List into a Menu

Is there a way to reduce the Lesson List into a shrunken menu when the course is viewed on a mobile device? I am really struggling with the new layout since the 2.0 update but I have edited most of the CSS to create a decent desktop site but the only way I can provide a decent mobile version is to either remove or reduce the size of the lesson list on mobile but need some support and I cannot see how to do this myself, despite lots of trying.

The page I need help with: [log in to see the link]