.button {
  border-radius: 4px;
  position: relative;
  background-color: #a1a1a1;
  border: none;
  color: #FFF;
  text-align: center;
  font-size: 18px;
  padding: 5px;
  transition: all 0.5s;
  margin: auto;
    width: 120px;
  text-align: center;
    -webkit-transition-duration: 0.4s; /* Safari */
    transition-duration: 0.4s;
    text-decoration: none;
    overflow: hidden;
    cursor: pointer;
}

.button span {
  cursor: pointer;
  display: inline-block;
  position: relative;
  transition: 0.5s;
}

.button span:after {
  content: '»';
  position: absolute;
  opacity: 0;
  top: 0;
  right: -20px;
  transition: 0.5s;
}

.button:hover span {
  padding-right: 25px;
border: none;
}

.button:hover span:after {
  opacity: 1;
  right: 0;
}

.button:after {
    content: "";
    background: #FFFFFF;
    display: block;
    position: absolute;
    padding-top: 300%;
    padding-left: 350%;
    margin-left: -20px!important;
    margin-top: -120%;
    opacity: 0;
    transition: all 0.4s
}

.button:active:after {
    padding: 0;
    margin: 0;
    opacity: 1;
    transition: 0s
}