<button onclick="location.href='http://www.savsesmoothies.com/'" class="button">Excellent!</button>

.button {
  position: relative;
  z-index: 1;
  border: 0;
  outline: 0;
  padding: 1.4em 1.4em 1.35em 1.4em;
  text-transform: uppercase;
  font-size: 22px;
  letter-spacing: 3px;
  color: #1a2026;
  -webkit-font-smoothing: antialiased;
  margin-top: 10%;
  font-weight: bold;
}

.button:before,
.button:after {
  content: "";
  position: absolute;
}

.button:before {
  background: white; 
  z-index: -1;
  top: .4em;
  left: .4em;
  right: .4em;
  bottom: .4em;
  
  -webkit-transition: all .15s;
  -moz-transition: all .15s;
  transition: all .15s;
}

.button:after {
  z-index: -2;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url(https://i.imgur.com/0sS2fDN.gif);
  background-position: center;
}

.button:hover:before {
  top: .1em;
  left: .08em;
  right: .08em;
  bottom: .1em;
}

body {
  text-align: center;
}