He has a good point: CSS can only define the appearance of existing HTML elements. Sometimes you need visual elements which doesn't correspond to any semantic H

He has a good point: CSS can only define the appearance of existing HTML elements. Sometimes you need visual elements which doesn't correspond to any semantic HTML element. I think SVG would be a good approach for designing these "unsemantic" visual elements, and you can use CSS with SVG. SVG would also be a good way to extend CSS beyound the built-in properties, eg. if I want to design a wawy border to apply to some elements. He also has a good point about the need for calculation in CSS. However I am really worried about the possible manitenance nightmare of a turing-complete CSS! It should be designed very carefully. A constraint-based sublanguage for CSS would perhaps make sense.