div.shadow {
  display: inline-block;
  vertical-align:top;
  text-align: center;
  margin: 20px;
  padding: 0px;
  color: #222;
  //-webkit-filter: grayscale(0.5);
  //filter: grayscale(1);
}

div.shadow:hover {
  background: #222;
  color: #fff;
  //-webkit-filter: grayscale(0);
  //filter: grayscale(0);
}