body {
    background: #444;
  }
  
  .play-btn {
    width: 100px;
    height: 100px;
    background: radial-gradient( rgba(255, 0, 128, 0.8) 60%, rgba(255, 255, 255, 1) 62%);
    border-radius: 50%;
    position: relative;
    display: block;
    margin: 384px auto;
    box-shadow: 0px 0px 25px 3px rgba(255, 0, 128, 0.8);
  }
  
  /* triangle */
  .play-btn::after {
    content: "";
    position: absolute;
    left: 50%;
    top: 50%;
    -webkit-transform: translateX(-40%) translateY(-50%);
    transform: translateX(-40%) translateY(-50%);
    transform-origin: center center;
    width: 0;
    height: 0;
    border-top: 15px solid transparent;
    border-bottom: 15px solid transparent;
    border-left: 25px solid #fff;
    z-index: 100;
    -webkit-transition: all 400ms cubic-bezier(0.55, 0.055, 0.675, 0.19);
    transition: all 400ms cubic-bezier(0.55, 0.055, 0.675, 0.19);
  }
  
  /* pulse wave */
  .play-btn:before {
    content: "";
    position: absolute;
    width: 150%;
    height: 150%;
    -webkit-animation-delay: 0s;
    animation-delay: 0s;
    -webkit-animation: pulsate1 2s;
    animation: pulsate1 2s;
    -webkit-animation-direction: forwards;
    animation-direction: forwards;
    -webkit-animation-iteration-count: infinite;
    animation-iteration-count: infinite;
    -webkit-animation-timing-function: steps;
    animation-timing-function: steps;
    opacity: 1;
    border-radius: 50%;
    border: 5px solid rgba(255, 255, 255, .75);
    top: -30%;
    left: -30%;
    background: rgba(198, 16, 0, 0);
  }
  
  @-webkit-keyframes pulsate1 {
    0% {
      -webkit-transform: scale(0.6);
      transform: scale(0.6);
      opacity: 1;
      box-shadow: inset 0px 0px 25px 3px rgba(255, 255, 255, 0.75), 0px 0px 25px 10px rgba(255, 255, 255, 0.75);
    }
    100% {
      -webkit-transform: scale(1);
      transform: scale(1);
      opacity: 0;
      box-shadow: none;
  
    }
  }
  
  @keyframes pulsate1 {
    0% {
      -webkit-transform: scale(0.6);
      transform: scale(0.6);
      opacity: 1;
      box-shadow: inset 0px 0px 25px 3px rgba(255, 255, 255, 0.75), 0px 0px 25px 10px rgba(255, 255, 255, 0.75);
    }
    100% {
      -webkit-transform: scale(1, 1);
      transform: scale(1);
      opacity: 0;
      box-shadow: none;
  
    }
  }