fluid-width video wrapper

I am (or attempting to) modifying the Amadeus theme under a child theme for my blog. Doing some experimenting with iframes and videos, and trying to get rid of the “fluid-width video wrapper” that shows up behind the top item (an object) here.
I’m definitely an amateur at best when it comes to this stuff but thought that by resizing the .fluid-width-video-wrapper in the child theme would work, but for some reason that isn’t being applied to the wrapper. I just want it gone for the object, and for the object to show up the size that it is.
Any ideas?
Thanks!