JSFiddle - React, Tailwind, and code Playground

HTML

<div class="votearrow" title="upvote"></div>

CSS

.votearrow {
  width: 10px;
  height: 10px;
  border: 0px;
  margin: 3px 2px 6px;
  background: url("http://news.ycombinator.com/grayarrow.gif") no-repeat;
}
@media (min-resolution: 2dppx), not all {
  .votearrow {
    background-size: 10px;
    background-image: url("http://news.ycombinator.com/grayarrow2x.gif");
  }
}