Your “.single_container” which has your content is positioned absolute. This causes divs to collapse and not be 100% wide. You need to add a width value to it to make sure it stretches all the way across.
The home page stretched across because of the wide image. In your 2nd link there’s only the table so it only stretches so far.
Sometimes in css it’s the not the addition of styles that breaks a page, but the lack of styles.