Your question threw me completely first time, when you said this:
I am working on a project with work, and it requires I use CSS selectors to locate elements within a webpage.
That sounds to me more like how it would be described in a server side forum, where a script is looking through a whole file for specific text. I think whgat you are trying to do is make the css relate
to the html.
Hopefully that ain't too pedantic.
I still am unable to help much but I find it strange that in the first line of html you posted, there is a div and two classes yet; someone has decided it a good idea to add inline css as well. Bit of a mess. It is I think a likely contributor to your problem.
I would hope the workflow of your project should include the server side guys, who can amend the css in the outputted documents and put it into the external css. Would make like easier for you.