According to the BB Theme Documentation, I am suppose to be able to modify the following in the customizer:
Navigation Background – you can configure a navigation background color as well as gradient here if you like.
Navigation Text – this section allows you to configure the navigation font, weight, case and size.
I can seem to find the settings for these. I don’t see them in the header settings.
Hey John,
Welcome to the BB forums! 
Those settings should be available under Appearance > Customize > Header > Nav Style. Although for the Navigation Background, that can only be set if you have your Header Layout set to either Nav Bottom or Nav Centered. For Nav Right, your navigation’s background will be the same as the header’s.
Hope this helps and let us know if we can assist further!
Ben
I have mine set as Nav Centered and it is not showing up with settings for the background.
https://www.evernote.com/l/AAFwX3ZNn6NLApzpLMgPAOs9LvzgHaTiV28
I don’t seem to have an option for Nav Style.
https://www.evernote.com/l/AAHX-thWzSVD1b0fkVMR0WS9J3snLW4Ivws
Hey John,
That’s weird! Do you think you can share temp admin access to your so we can check? You can post the details here using the private reply option below.
Ben
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Hey John,
This is actually caused by the function you have that removes the Nav Style section on the customizer. Removing the line $wp_customize->remove_section( 'fl-nav-style' ); on your custom function should fix you right up!
Ben
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No worries at all, John! Have fun!
Ben