.grayscale {
  /* Firefox 10+, Firefox on Android */
  filter: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg'><filter id='grayscale'><feColorMatrix type='matrix' values='0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0'/></filter></svg>#grayscale");

  /* IE 6-9 */
  filter: gray;

  /*
    Chrome 19+,
    Safari 6+,
    Safari 6+ iOS,
    Opera 15+
  */
  -webkit-filter: grayscale(100%);
}

.grayscale.grayscale-fade {
  -webkit-transition: -webkit-filter .5s;
}

.grayscale.grayscale-fade:hover {
  -webkit-filter: grayscale(0%);
  filter: none;
}

.grayscale-replaced.grayscale-fade svg {
  opacity: 1;
  -webkit-transition: opacity .5s ease;
  transition: opacity .5s ease;
}

.grayscale-replaced.grayscale-fade:hover svg {
  opacity: 0;
}