Биение сердца на чистом CSS3

HTML

<div class="demo">
   <div id="heart"><div class="k"></div></div>
</div>

CSS

body {
    margin: 0;
    padding: 0;
    background: #fff;
}
.demo{
  bottom: 0;
  height: 120px;
  left: 0;
  margin: auto;
  position: absolute;
  top: 0;
  right: 0;
  width: 120px;
}
/* Сердце */
#heart {
  position: relative;
  width: 100px;
  height: 90px;
  margin: 0 auto;
  animation: b 1.5s ease-in-out infinite;
}

#heart:before,
#heart:after {
  position: absolute;
  content: "";
  left: 50px;
  top: 0;
  width: 50px;
  height: 80px;
  background: red;
  -moz-border-radius: 50px 50px 0 0;
  -webkit-border-radius: 50px;
  border-radius: 50px 50px 0 0;
  -moz-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
  transform: rotate(-45deg);
  -moz-transform-origin: 0 100%;
  -ms-transform-origin: 0 100%;
  -webkit-transform-origin: 0 100%;
  transform-origin: 0 100%;
}

#heart:after {
  left: 0;
  -moz-box-shadow: 3px -45px 5px 3px rgba(255, 255, 255, 0.5);
  -webkit-box-shadow: 3px -45px 5px 3px rgba(255, 255, 255, 0.5);
  box-shadow: 3px -45px 5px 3px rgba(255, 255, 255, 0.5);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
  transform: rotate(45deg);
  -moz-transform-origin: 100% 100%;
  -ms-transform-origin: 100% 100%;
  -webkit-transform-origin: 100% 100%;
  transform-origin: 100% 100%;
}

.k {
  position: absolute;
  top: 16px;
  left: 55px;
  z-index: 3;
  width: 0px;
  height: 0px;
  animation: a 10.0s infinite;
}

@keyframes a {
  0% {
    -moz-box-shadow: 0 0 65px 15px rgba(255, 255, 255, 0.5);
    -webkit-box-shadow: 0 0 65px 15px rgba(255, 255, 255, 0.5);
    box-shadow: 0 0 65px 15px rgba(255, 255, 255, 0.5);
  }
  50% {
    -moz-box-shadow: 0 0 65px 25px rgba(255, 255, 255, 0.5);
    -webkit-box-shadow: 0 0 65px 25px rgba(255, 255, 255, 0.5);
    box-shadow: 0 0 65px 25px rgba(255, 255, 255, 0.5);
  }
  100% {
    -moz-box-shadow: 0 0 65px 15px rgba(255, 255, 255, 0.5);
    -webkit-box-shadow: 0 0 65px 15px rgba(255, 255, 255, 0.5);
   ...