<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">

<defs>
	<linearGradient id="g1">
		<stop offset="0" stop-color="red"/>
		<stop offset="1" stop-color="blue"/>
	</linearGradient>
	<linearGradient id="g2">
		<stop offset="0" stop-color="green"/>
		<stop offset="1" stop-color="yellow"/>
	</linearGradient>
</defs>
<style type="text/css"><![CDATA[
	rect {
		stroke: red;
		stroke-width: 10;
		fill:url(#g1)
	}
]]></style>

<style type="text/css">.circ { fill: none; stroke: url("#g2"); stroke-width: 15 }</style>

<rect height="300" width="300"/>
<circle class="circ" cx="350" cy="350" r="40"/>

</svg>