<!DOCTYPE html>
<html lang="en-US">
<body>
<svg height="100" width="100">
<defs>
<radialGradient id="grad" cx="50%" cy="50%" r="50%" fx="50%" fy="50%">
<stop offset="0%" style="stop-color:black;stop-opacity:0" />
<stop offset="100%" style="stop-color:gold;stop-opacity:1" />
</radialGradient>
</defs>
<circle cx="50" cy="50" r="40" fill="url(#grad)" />
</svg>
</body>
</html>