The box is just an example, the real subject of the post is the list under “A few consequences with how CSS does its thing”. And all those examples really are p

The box is just an example, the real subject of the post is the list under “A few consequences with how CSS does its thing”. And all those examples really are pixel-perfectness (pixel-perfect text boxes, pixel-perfect alignment of different fonts, pixel-perfect vertical centering of text in a button).