.btn{
  a{
    display:block;
    background:#ff0000;
    width:300px;
    padding:20px;
    text-align:center;
    border-radius:30px;
    margin-left:auto;
    margin-right:auto;
    margin-top:60px;
    color:#ffffff;
    animation: blink-btn 0.5s linear infinite normal;
    &:hover{
  	  animation:none;
      background:#ffcc00;
    }
  }

}
@keyframes blink-btn{
	0% {
    box-shadow:0px 0px 0px 0px rgba(255,0,0,1);
  }
	100% {
    box-shadow:0px 0px 0px 5px rgba(255,0,0,0.6);
  }
}