scroll, like we say that the background scroll together with the page but when I scroll the entire page, nothing seems to happen.fixed, it's a bit confusing, we say it's attached to the viewport, it is supposed to move?local means it scroll when we scroll the content in the container itself. By the way, the local value has many use case, no? I see I often see things like that on the web, like while we are scrolling down, an image is kind of moving, I don't know if it's a parallax effect or something else though :c.