When I posted that comment My view was that layout would still be primarily driven by higher level style properties, but after I posted I though about it some more and I realized if done properly you could probably the css value language could theoretically do it all. If it were to generate values for the complete layout, bypassing the higher level layer, effectively telling the display engine that everything was absolutely positioned and in the right place already.

I don't think I would advocate for that to be the standard way to implement layout, but it should be at least possible.

Similarly I think the system should be capable of specifying a table where each cell has a background colour corresponding to its position in a Mandelbrot set. I don't think people should be doing that normally either, but I certainly think it should be something that is capable.