<svg xmlns="http://www.w3.org/2000/svg">
  <linearGradient id="gradient" x2="0%" y1="100%">
    <stop stop-color="#008000" offset="0.5"/>
    <stop stop-color="#ff0000" offset="0.5"/>
    <set attributeName="y2" to="200%" fill="freeze"/>
  </linearGradient>
  <rect width="100" height="100" fill="#ff0000"/>
  <rect width="100" height="100" fill="url(#gradient)"/>
</svg>