.heartbeat {
    -webkit-animation: heartbeat 1.5s ease-in-out infinite both;
            animation: heartbeat 1.5s ease-in-out infinite both;
}

@-webkit-keyframes heartbeat {
  from {
    -webkit-transform: scale(1);
            transform: scale(1);
    -webkit-transform-origin: center center;
            transform-origin: center center;
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
  10% {
    -webkit-transform: scale(0.91);
            transform: scale(0.91);
    -webkit-animation-timing-function: ease-in;
            animation-timing-function: ease-in;
  }
  17% {
    -webkit-transform: scale(0.98);
            transform: scale(0.98);
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
  33% {
    -webkit-transform: scale(0.87);
            transform: scale(0.87);
    -webkit-animation-timing-function: ease-in;
            animation-timing-function: ease-in;
  }
  45% {
    -webkit-transform: scale(1);
            transform: scale(1);
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
}
@keyframes heartbeat {
  from {
    -webkit-transform: scale(1);
            transform: scale(1);
    -webkit-transform-origin: center center;
            transform-origin: center center;
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
  10% {
    -webkit-transform: scale(0.91);
            transform: scale(0.91);
    -webkit-animation-timing-function: ease-in;
            animation-timing-function: ease-in;
  }
  17% {
    -webkit-transform: scale(0.98);
            transform: scale(0.98);
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
  33% {
    -webkit-transform: scale(0.87);
            transform: scale(0.87);
    -webkit-animation-timing-function: ease-in;
            animation-timing-function: ease-in;
  }
  45% {
    -webkit-transform: scale(1);
            transform: scale(1);
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
}