<div id="css3">
                   <svg id="gradient">
                       <defs>
                           <linearGradient id="linearGradient2">
                               <stop offset="0%" style="stop-color: red;stop-opacity:1" />
                               <stop offset="50%" style="stop-color: blue;stop-opacity:0.5" />
                               <stop offset="100%" style="stop-color: yellow;stop-opacity:1" />
                           </linearGradient>
                           <linearGradient id="linearGradient3" xlink:href="#linearGradient2" x1="0" y1="0" x2="300" y2="150" gradientUnits="userSpaceOnUse" />
                       </defs>
                       <rect class="gradient" width="300px" height="150px" style="fill: url(#linearGradient3)" />
                   </svg>
               </div>