<svg xmlns="http://www.w3.org/2000/svg" version="1.1"
     width="100" height="20"
     viewBox="0 0 100 20">
  <!-- animated value for preserveAspectRatio: -->
  <set attributeName="preserveAspectRatio" to="xMaxYMax slice"/>
  <rect x="2" y="2" width="96" height="16"
        style="stroke-width: 4; fill:lime; stroke: teal"/>
</svg>