Edit in JSFiddle

<div class="infinite-line"></div>
.infinite-line {
  background: url(data:image/svg+xml;base64,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) repeat-x;
  width: 100%;
  height: 50px;
  
  animation: animate 3s linear infinite;
}

@keyframes animate {
  from {
    background-position: 0px 0px;
  }
  
  to {
    background-position: 400px 0px;
  }
}