`<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="300" height="80">
  <rect id="rect1"  x="160" y="10" width="60" height="60" fill="blue"/>
    <style>
      rect:hover{opacity: 0.5;}
    </style>
</svg>`