CSS for centered content not working for entire site

Hi team,
I have asked help twice in my previous ticket but I received no answer.
The problem is that the code below sent me some days ago:

#top .post-entry {
max-width: 800px !important;
left:50%;
transform:translate(-50%);
}

works fine only at post level: content is centered.
But it broke the site format everywhere else (homepage, category page…).
Please refer to the screenshots of the broken pages to see the messy format.
Thanks again.
p.s. I removed the code to allow my site to work well. If you need to verify the problem please let me know and I will put it again at Quick CSS.