Darken background when Cart drops down

I’ve run into a little problem. My designers would like to have the page darken when the cart dropdown opens. I’m able to do this for a dropdown I create myself using animations and this guide: How do I darken the rest of the page behind a Dropdown menu?

However, with the cart, I don’t have access to the open/close animation, so can’t use it to affect parts of the site that aren’t within the cart. As such, I’ve tried creating a background within the cart, making it absolute, and designing it to cover the page. In the webflow developer section, this works and looks like this:

But in testing it breaks and looks like this:

So, simple question, is there a way to either interact with the actual cart dropdown animation, or otherwise push a black background behind the cart dropdown?

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

Hi! Your read-only link doesn’t work.

Whoops. Sorry about that. Fixed.