How to make an adaptive background for blocks?

Question

Layout

Have a nice day everyone. I am just getting used to layout and so I decided to make the first layout. Can you tell me why the background image and background color give out a white bar when the site is reduced?
Thanks in advance for your reply.

Answer 1

Most likely, the header is too wide, it is clear that the button is too long and breaks everything.

Answer 2

it often happens, this is a layout error in bootstrap. I would delete the blocks one by one directly in the browser until the strip disappears to determine where the error is, then I would look in the block where there are layout errors. It seems to me that the .container>.row>.col construction is wrong somewhere
PS in support of Magnet19 's answer , perhaps he is right, look in the header, there may be no container, or the design error that I indicated may be at the top in the navigation panel.