Text extending out of sight on pages with no side menu

I’m using a custom theme of wordpress. The site has an issue where when a page has no parent page i.e. Coming straight from the home page with no other pages tied to it.

The text extends too far to the right. I have tried changing content px but it only changes it for pages with a side menu and not pages without a side menu.

You can see an example here of the problem with text going out to the right
https://www.wmimmigration.com/document-checking-service/

and here where it is fine due to the menu on the left
https://www.wmimmigration.com/tier-4-visa/confirmation-of-acceptance-for-studies/

Has anyone any suggestions as the solution I tried hasn’t worked and I think I’m a in a little over my head. If I knew which setting to change in the style.css to keep the text from going out on the right I should be able to fix it.