[blablabla123]

> Try covering dynamic-sized image with an svg surface.

You could embed the dynamic-sized image within an svg, perhaps even a fully dynamic inline svg.

> Try outlining a hovered element so that outline/shadow covers other items around. Try to baseline align text in non-shallow div hierarchy

I mean at some point you need to use JS. Still, IMHO it's quite amazing how far you can go with a purely declarative language. That also means a myriad of side effects including smooth reflow being taken care of automatically as long as best-practices are followed. Is there any way to write these examples completely declaratively in GTK+/Cairo, NSView or QPainter?