Bootstrap navbar-fixed-top

PHPR 9.6 bootstrap
Hi together, I' still learning bootstrap.
I'm working on a page with many views and a lot of data. So when scolling down I wanted to keep the navbar visible.
I enhanced the navbar class with "navbar-fixed-top" and it works like it should.
To make it suitable to the rest of the page I put a style="margin-top:50px" to the breadcrump menu. (otherwise the stuff is hiding behind the navbar)
Two questions:

1. Is there a way to do this automatically (e.g. in custom CSS) without modifying page by page in html mode. ( I use the new reordering,show,hide Feature)
   
2. The top end of the vertical scrollbar is also visible in the navbar now. (all Browsers) How can I avoid this?
   Thx in advance for your help!!
   Andreas