Overlap content from one section to another

I’ve been playing with overlapping content from one section to another. In the below screenshot The section of the website has a fill colour of grey and I have a content width container to mange my content width coloured red.

In the screenshot I used margin -200 on the content width board. The issue that I can see if that the section is smaller than the content width board. If I were the apply margin -200 on the section there’s no issue.

Based on the controls that I’m using is this a bug or expected behavior?

How do you overlap content from one section to another?