Additional CSS not overwriting page CSS

I’m trying to change the color of a single page and remove the title + title icon. I am using the code snippets:
.page-id-2128 .site-content-contain {
background-color: #e0e0e0;
}

.page-id-2128 .entry-title display: none;

So the page should be all grey and there shouldn’t be a title slot, right? Well, unfortunately not for me. Anyone able to help me out?

The page in question:
http://www.societyfordiversity.org/about-us/