Can someone help me with this strange phenomena?

When I am editing my websites in the Safari web browser there is no strange white box behind my content section,
But when I review my website in another browser like Google Chrome, there appears to be a white band/box behind my first content section.
Firstly I added the background picture under the global site settings, then I tried to ad the picture to every single page but this did not resolve the problem.
Very strange, hopefully someone can help me here, thank you.

