Edit in JSFiddle

<div class="yy"></div>

.yy {
  margin: 50px auto;
  width: 250px;
  height: 250px;
  border-left: 20px solid #3ACFD5;
  border-right: 20px solid #3a4ed5;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  background-position: 0 0, 0 100% ;
  background-repeat: no-repeat;
  -webkit-background-size: 100% 20px;
  -moz-background-size: 100% 20px;
  background-size: 100% 20px;
  background-image: url(data:image/svg+xml;base64,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),url(data:image/svg+xml;base64,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);
  background-image: -webkit-linear-gradient(left, #3acfd5 0%, #3a4ed5 100%), -webkit-linear-gradient(left, #3acfd5 0%, #3a4ed5 100%);
  background-image: -moz-linear-gradient(left, #3acfd5 0%, #3a4ed5 100%), -moz-linear-gradient(left, #3acfd5 0%, #3a4ed5 100%);
  background-image: -o-linear-gradient(left, #3acfd5 0%, #3a4ed5 100%), -o-linear-gradient(left, #3acfd5 0%, #3a4ed5 100%);
  background-image: linear-gradient(to right, #3acfd5 0%, #3a4ed5 100%), linear-gradient(to right, #3acfd5 0%, #3a4ed5 100%);
}