I had that same idea more than once, to propose a local per-element media query. In fact the concept itself of querying the whole window to understand the dime

I had that same idea more than once, to propose a local per-element media query. In fact the concept itself of querying the whole window to understand the dimension a portion of it will occupy... well it's strange. At the same time, have you considered the implications of such a structure? A local media query could change the queried properties. Dangerously recursive. In fact you COULD reach what you want using seamless iframes. I tinkered my head with such an option sometimes.