#login {
width: 100%;
background-color: #e2e2e2;
margin-top: 250px;
position: absolute;
top: 0;
}

#center {
width: 500px;
position: absolute;
left: 0;
right: 0;
top: 0;
bottom: 0;
margin: auto;
max-width: 100%;
max-height: 80%;
overflow: auto;
display: table;
}

#content {
display: table-cell;
vertical-align: middle;
}