html {
width: 100%;
height: 100%;
}
body {
width: 100%;
height: 100%;
margin: 0px;
position: relative;
}
div.shadow {
position: absolute;
max-width: 45%;
max-height: 45%;
top: 50%;
left: 50%;
overflow: visible;
}
img.logo {
position: relative;
max-width: 100%;
max-height: 100%;
margin-top: -50%;
margin-left: -50%;
}