Changing content background color

Hi there,

I’m trying to change the content background color for a site. I tried this CSS:
.page-id-69 div#content {
background: red !important;
}

and it’s not working. I can change the overall background, and text box colors, but I want the white box of the content removed.

Here is a screenschot: https://imgur.com/a/jDUJVWG