Fixed nav bar covering WP user tool bar

With the help of some awesome people here I’ve finally managed to get a fixed nav bar on my blog with a width the same size as my content: https://hearnshtest07.org

However, now I’ve been roaming the internet in search of an answer to a new problem and simply cannot find one, so I turn to you guys once more!

The problem is that, when logged into the site or into my wordpress.com account, the fixed nav bar covers the wp toolbar and looks really sloppy. I haven’t tried it with another sort of frame or bar but I suspect the result would be the same, so I’m wondering:
Anyone know the proper way to remove the wp toolbar from a blog altogether (for the admin as well as for other users/readers), OR how to make some sort of contingency code so that when a frame or bar is detected, there is extra space for it to be displayed above the navigation?
Or anyone have any tutorial suggestions? Would love any hep at all.

Cheers!
Sophie