#overlay {
    position: fixed; /* Sit on top of the page content */
    display: none; /* Hidden by default */
    width: 100%; /* Full width (cover the whole page) */
    height: 100%; /* Full height (cover the whole page) */
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0,0,0,0.5); /* Black background with opacity */
    z-index: 2; /* Specify a stack order in case you're using a different order for other elements */
    cursor: pointer; /* Add a pointer on hover */
}

.loader,
.loader:before,
.loader:after {
    border-radius: 50%;
    width: 2.5em;
    height: 2.5em;
    -webkit-animation-fill-mode: both;
    animation-fill-mode: both;
    -webkit-animation: load7 1.8s infinite ease-in-out;
    animation: load7 1.8s infinite ease-in-out;
}
.loader {
    color: #ffffff;
    font-size: 10px;
    margin: 80px auto;
    position: relative;
    text-indent: -9999em;
    -webkit-transform: translateZ(0);
    -ms-transform: translateZ(0);
    transform: translateZ(0);
    -webkit-animation-delay: -0.16s;
    animation-delay: -0.16s;
}
.loader:before,
.loader:after {
    content: '';
    position: absolute;
    top: 0;
}
.loader:before {
    left: -3.5em;
    -webkit-animation-delay: -0.32s;
    animation-delay: -0.32s;
}
.loader:after {
    left: 3.5em;
}
@-webkit-keyframes load7 {
    0%,
    80%,
    100% {
        box-shadow: 0 2.5em 0 -1.3em;
    }
    40% {
        box-shadow: 0 2.5em 0 0;
    }
}
@keyframes load7 {
    0%,
    80%,
    100% {
        box-shadow: 0 2.5em 0 -1.3em;
    }
    40% {
        box-shadow: 0 2.5em 0 0;
    }
}