I am familiar with styling specific pages on WordPress by adding a class

.page-id-123

in front of the styled element. However, this doesn’t seem to apply to “subpages” (sorry don’t know what they are called), when after the page, there is a specific tag (?) added.

Example:

URL: wordpressweb.com/my-account

CSS: .page-id-123 .header { background-color: yellow; }

URL: wordpressweb.com/my-account/?add-new-business=true

CSS: ??? .header { background-color: yellow; }

Is there a way to target these kind of pages with CSS?