Background being cropped on mobile

I’m in the process of trying to lay the landing page of my site out to look neater on mobile browsers. I’m doing this by adjusting the margins and padding of all the necessary columns and content.

However, whenenever I shrink the browser to a certain resolution, it begins to crop the right side of the main section background image off.

I cannot find how to prevent the cropping from happening or finding the fields that adjust said background image to expand width-wise.

Please help. The following is my site, you will see what I mean when you look at it on desktop vs mobile (larger to smaller resolutions):

https://plursearch.org/

If you shrink the desktop browser window, at a certain point it just begins to crop the main section background image on the right side….

Thank you.