Sounds like they just dropped in Chrome Canary, so this is very, very early. That typically means it'll take years for it to be supported in all browsers or 99% of browser versions in use. Is there a polyfill solution for this in the meantime?
[1] https://github.com/w3c/csswg-drafts/issues/5796
[2] https://philipwalton.com/articles/responsive-components-a-so...