Sizing demo

This is an realtime demo of the Logical sizing properties spec

Change the value of the size property to see live changes in the demo block and resize the browser to see aspect changing.

      
        .demo-block {
          background: url(https://fillmurray.com/2000/1000) center center / cover;
          size: 80% 40px / calc(2/1) / 100px border-box;
        }