argyleink/prop-for-that: what JS knows, now CSS knows

Sliders, pointer position, element visibility, viewport size, battery, network, sensors — JavaScript can read all of it; CSS can't. prop-for-that writes that runtime state into --live-* and --const-* custom properties — batched and diffed down to one setProperty per frame — so your CSS can compose and react to it with plain calc() and var().