The alignment is an oversight with the author's mockup. His post is focused on the vertical rhythm and the proportions on the Y-axis. If I'm not mistaken, the

The alignment is an oversight with the author's mockup. His post is focused on the vertical rhythm and the proportions on the Y-axis. If I'm not mistaken, the author doesn't take issue with the proportions on the x-axis and makes the mistake of keeping things tightly aligned to the horizontal grid/x-axis proportions. Consequently, he missed some of the subtle things in the original.