.loading {
position: absolute;
top: 50%;
left: 50%;
height: 100px;
width: 100px;
margin-left: -50px;
margin-top: -50px;
line-height: 100px;
vertical-align: middle;
}
.fondo {
background-color: rgba(230, 230, 230, 0.9);
bottom: 0;
float: left;
height: 100%;
left: 0;
opacity: 0.9;
position: absolute;
right: 0;
top: 0;
width: 100%;
}