--description--

Here's one more continuous animation example with the animation-iteration-count property that uses the heart you designed in a previous challenge.

The one-second long heartbeat animation consists of two animated pieces. The heart elements (including the :before and :after pieces) are animated to change size using the transform property, and the background div is animated to change its color using the background property.

--instructions--

Keep the heart beating by adding the animation-iteration-count property for both the back class and the heart class and setting the value to infinite. The heart:before and heart:after selectors do not need any animation properties.

--hints--

The animation-iteration-count property for the heart class should have a value of infinite.

assert($('.heart').css('animation-iteration-count') == 'infinite');

The animation-iteration-count property for the back class should have a value of infinite.

assert($('.back').css('animation-iteration-count') == 'infinite');

--seed--

--seed-contents--

<style>
  .back {
    position: fixed;
    padding: 0;
    margin: 0;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: white;
    animation-name: backdiv;
    animation-duration: 1s;

  }

  .heart {
    position: absolute;
    margin: auto;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: pink;
    height: 50px;
    width: 50px;
    transform: rotate(-45deg);
    animation-name: beat;
    animation-duration: 1s;

  }
  .heart:after {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: 0px;
    left: 25px;
  }
  .heart:before {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: -25px;
    left: 0px;
  }

  @keyframes backdiv {
    50% {
      background: #ffe6f2;
    }
  }

  @keyframes beat {
    0% {
      transform: scale(1) rotate(-45deg);
    }
    50% {
      transform: scale(0.6) rotate(-45deg);
    }
  }

</style>
<div class="back"></div>
<div class="heart"></div>

--solutions--

<style>
  .back {
    position: fixed;
    padding: 0;
    margin: 0;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: white;
    animation-name: backdiv;
    animation-duration: 1s;
    animation-iteration-count: infinite;
  }

  .heart {
    position: absolute;
    margin: auto;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: pink;
    height: 50px;
    width: 50px;
    transform: rotate(-45deg);
    animation-name: beat;
    animation-duration: 1s;
    animation-iteration-count: infinite;
  }
  .heart:after {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: 0px;
    left: 25px;
  }
  .heart:before {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: -25px;
    left: 0px;
  }

  @keyframes backdiv {
    50% {
      background: #ffe6f2;
    }
  }

  @keyframes beat {
    0% {
      transform: scale(1) rotate(-45deg);
    }
    50% {
      transform: scale(0.6) rotate(-45deg);
    }
  }
</style>
<div class="back"></div>
<div class="heart"></div>