max-height: 100%;
max-width: 100%;
position: absolute;
top: 50%;
left: 50%;
-webkit-transform: translate(-50%, -50%);
-moz-transform: translate(-50%, -50%);
-ms-transform: translate(-50%, -50%);
-o-transform: translate(-50%, -50%);
transform: translate(-50%, -50%);
