Index background white margins


#1

Hey There!

I´m a beginner at jekyll website coding. And currently i face my first problem:

At my index page I´ve got a big background image, which covers most of the page, but not everything.
The navigation bar has a white frame. See my screenshot. I want it to “be in front” of my background img.

Maybe someone can help me out. Thanks alot!

Capture