CSS

box shadow css animation

.box-shadow {
  box-shadow: 0 3px 5px 0 rgba(0,0,0,0.08);
  transition: box-shadow 0.3s ease-in-out;
}

css animation box shadow

<div class="box">Box</div>
<style>
.box {
    width: 300px;
    padding: 40px 0;
    font: bold 46px sans-serif;
	text-align: center;
    background: #ccc;
    border: 1px solid #999;
    -webkit-animation: test 4s infinite; /* Chrome, Safari, Opera */
    animation: test 4s infinite;
}
/* Chrome, Safari, Opera */
@-webkit-keyframes test {
    50% {box-shadow: 8px 8px 16px #999;}
}
/* Standard syntax */
@keyframes test {
    50% {box-shadow: 8px 8px 16px #999;}
}
</style>