Responsive Web Typography Variable Fonts Demo
Demonstration of typographic possibilities with and implementation of the new variable font format.
At this time the best way to view is with Chromoe (Mac or Win) with Experimental Web Features enabled, but it's also possible with beta of Mac OS High Sierra or with the nightly build of Firefox.
I'll update this as browser support and the CSS implementation becomes more widely available and implemented. Many, many thanks to @litherum (https://github.com/litherum) for making this possible!