Because the messages button only shows up on the individual listing page or the host/vendor’s profile page, I selected those 2 pages
Then I narrowed the CSS selection to the popup modal
But because a non-logged-in user would first see a login popup modal when trying to message a user, I used the :not selector to not allow the resizing on the login modal (which luckily has a unique CSS ID)
As an added bonus, this code also expands the size of the “Report Listing” popup modal to allow the user to input a lengthier message if necessary.