.w-450 {
	width: 450px;
	background-color: white;
}
body{
	
	background-image: url("tau19.jpg");
	background-size: 100%;
}
.btn{
	display: block;
	margin-left: 40%;
	margin-right: 40%;
	margin-top: 30px;
	margin-bottom: 30px;
	text-align: center;
  }