how to properly space content below a navbar

[tacman]

I love the theme options, thanks for releasing this!

Is there a class to apply to the body or container to properly space the main page content below the navbar? For example, with materia:

And with sandstone

In both cases the content is too high, I'm guessing there's a class somewhere to determine the margins.

Your example page for each theme has all the navbars in a block, by chance are there example pages with a navbar at the top of the page that I can use to see how to properly setup the body and container?

[tacman]

If I remove the fixed-top class in navar, it works as expected. Am I missing something for setting fixed-top css?

I changed the class to sticky-top and it seems to be working for me.