Pages were white and ink was black so all it took was no imagination. While we're at it can we discuss the stupidity of retaining the qwerty keyboard? It was designed to slow down typers so the arms (remember those?) didn't get stuck together. No more arms clacking, but we still suffer the design.
I don't "suffer" the design. I like it. It's what I learned to type on, and I'm not aware of any alternative that's any better. Why do you think it's so horrible?