The issue is that the CSS isn't being included when the media type is print.
<link href="/SomeProject/static/bundle-bundle_bootstrap_head.css" type="text/css" rel="stylesheet" media="screen, projection">
That only includes the CSS for screen and projection.
Regarding your comment: I'm very sure that if the media attribute on the link element doesn't include print
then the CSS won't be parsed when printing.
Thus the media query within the CSS never gets a chance to run at all. If you look at the getbootstrap.com site you will see it doesn't include a media specification on the style sheet and thus is processed for all media types (including print).