.wave-effect {
  position: relative;
  overflow: hidden;
  
  .material-circle {
    width: 0px;
    height: 0px;
    position: absolute;
    background: black;

    &.animated {
      opacity: 0.2;
      -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=20)";
      -webkit-animation: btn-touch 0.75s ease-out;
      animation: btn-touch 0.75s ease-out;
    }
  }
}
