SOURCE

<a class="bbns fen" href="#pg_ms">11元秒杀</a>

.fen {
    background: #f73ece;
    background-image: -webkit-linear-gradient(to right, #ef13b4, #ff6eec);
    background-image: linear-gradient(to right, #ef13b4, #ff6eec);
}
.bbns {
    display: inline-block;
    width: 130px;
    height: 30px;
    line-height: 30px;
    text-align: center;
    border-radius: 30px;
    color: #fef99e;
    margin: 0 auto 10px;
    border-bottom: 2px solid rgba(0,0,0,0.6);
}

.bbns {
    animation-name: lighting;
    -webkit-animation-name: lighting;
    animation-duration: 1s;
    -webkit-animation-duration: 1s;
    animation-iteration-count: infinite;
    -webkit-animation-iteration-count: infinite;
}

@-webkit-keyframes lighting {
  0% {
    transform: translateY(0%);  
  }
  50% {
     box-shadow: 0 0 15px #fff;
  } 
  100% {
    transform: translateY(0%);
  }    
}