html, body {
   height: 100%;
   width: 100%;
   margin: 0;
   padding: 0;
   background-color: black;
}

#atilivs {
	position: relative;
	top: 50%;
	transform: translateY(-50%);
	height: 200px;
	background-image: url('../img/a.png');
	background-repeat: no-repeat;
	background-position: center;
	display: none;
}

.center {
	width: 100%;
	height: 100%;
}