Apparently the website navigation looks completely broken in Internet Explorer (11) (see attached screenshot).

I do not have IE myself, but am using the website BrowserStack to see what the website looks like on various browser versions

You will investigate the reason for this and try to find what aspect of the css is not working, and try to fix it.

The navbar uses bootstrap classes in combination with some custom css.
All the css/less lives in the repo folder src/client/stylesheets