<svg width="300" height="200"
  xmlns="http://www.w3.org/2000/svg"
  xmlns:html="http://www.w3.org/1999/xhtml">
  <title>Rectangle coordinates and sizes specified by percentage</title>
  <html:link rel="help" href="https://w3c.github.io/svgwg/svg2-draft/geometry.html"/>
  <html:link rel="match"  href="rect-ref.svg" />
  <style>
    rect {
      x: 10%;
      y: 30%;
      width: 40%;
      height: 50%;
      fill: blue;
    }
  </style>
  <rect />
</svg>