I've noticed in the book of Jason Beaird on p. 99 something that could possibly be an error.
It's within "background-position" paragraph:
It's written like that:
"...If we wanted to position the image 300 px from the left edge, and 400 px from the top, we could use the declaration
background-position: 300px 200px
And then there's an image and below it, it says:
background-position: 300px 400px;
Please let me know