body{
    background-size: cover;
}
#login_panel{
    display: table;
    width: 100%;
    height: 100%;
}
#login_panel > div{
    display: table-cell;
    vertical-align: middle;
    text-align: center;
}
#login_panel input[type="text"], #login_panel input[type="password"]{
    margin-bottom: 39px;
}