> There’s far more than rectangles at work when you actually need to render things in a browser. Indeed. You're entirely correct. But with CSS the basis is th

> There’s far more than rectangles at work when you actually need to render things in a browser. Indeed. You're entirely correct. But with CSS the basis is that general "everything is a rectangle" model - which makes it easier to adapt to new features when they're introduced - compared to having to basically learn-from-scratch when new layout features are added to other systems.