hr {
  border: 0;
  height: 1px;
  background: gray;
  background-image: -webkit-linear-gradient(left, #fff, gray, #fff);
  background-image: -moz-linear-gradient(left, #fff, gray, #fff);
  background-image: -ms-linear-gradient(left, #fff, gray, #fff);
  background-image: -o-linear-gradient(left, #fff, gray, #fff);
}