@Pinkeltje: Do you have a sample layout (template/bootstrap styling) which you can show to us so that we can try to make the default style for the module ?
Forget about my previous post. Think it won't work.
Had some spare time to look into your module. Made some changes to css and default.php. As far as I can see functions the same as original module, but now inherits style from template and one can use module class suffix. For that I replaced #edocmanmenu by .edocmanmenu.
Attached only changed files.