.heart {
  background-color: red;
  display: inline-block;
  height: 50px;
  margin: 0 10px;
  position: relative;
  top: 0;
  left: 45%; top: 45%;
  transform: rotate(-45deg);
  position: absolute;
  width: 50px;
}

.heart:before,
.heart:after {
  content: "";
  background-color: red;
  border-radius: 50%;
  height: 50px;
  position: absolute;
  width: 50px;
}

.heart:before {
  top: -25px;
  left: 0;
}

.heart:after {
  left: 25px;
  top: 0;
}

@keyframes heartbeat {
    0% {
      transform: scale( 1 );    
    }
    20% {
      transform: scale( 1.25 ) 
        translateX(5%) 
        translateY(5%);
    } 
    40% {
      transform: scale( 1.5 ) 
        translateX(9%) 
        translateY(10%);
    }
  }

.heart {
    animation: heartbeat 1s infinite;
}