Hello.
I have a question about the first paragraph of the task, which is:
quote - You can use CSS to make elements with this class completely hidden from the visual page, but still be announced by screen readers. - unquote.
Why would I want to keep something visually hidden but be announced by screen readers?
Maybe you have an image or a graphic for the sighted users, but to convey that same information to visually impaired users, you need text, which instead you may want to hide from the sighted users