gecko-dev/layout/reftests/css-gradients/radial-premul-ref.html

<div style="background: radial-gradient(rgba(255, 0, 0, .9) 0% , rgba(255, 0, 0, 0) 50%, rgba(0, 0, 255, 0) 50%, rgba(0, 0, 255, 1) 100%) no-repeat; width: 300px; height: 300px;"><br></div>