Hey Stefan!
Just on the outside chance you haven't received an answer or found it by now -
If you look on the right side of your phone screen, adjacent to the Project name there is a small box - that is the nav-collapse feature of the bootstrap system. It saves screen space but is confusing and I believe it's not that intuitive, but someone does. If you remove the nav-collapse div you'll get your whole navigation bar, responsively we hope!