How do I Hide the container box

Hello this is my first Blog and I’m pretty much a beginner with CSS and HTML, word press. I want to Hide the container box my post are in on my site so all you see is the Background beneath it. I don’t want to delete it because from what I’ve read search engines need it to find post etc. so deleting the code is out, any help would be great. If you could please be as specific as possible because like I said I’m still learning.

Thanks in advance
Lorrin
https://subleveltransmission.com/