#spinner {
    display: none;
    position: fixed;
    z-index: 999;
    height: 2em;
    width: 2em;
    overflow: show;
    margin: auto;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
}

/* Transparent Overlay */
#spinner::before {
    content: '';
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.3);
}

/* :not(:required) hides these rules from IE9 and below */
#spinner:not(:required) {
    /* hide "loading..." text */
    font: 0/0 a;
    color: transparent;
    text-shadow: none;
    background-color: transparent;
    border: 0;
}

#spinner:not(:required):after {
    content: '';
    display: block;
    font-size: 10px;
    width: 1em;
    height: 1em;
    margin-top: -0.5em;
    -webkit-animation: spinner 150ms infinite linear;
    -moz-animation: spinner 150ms infinite linear;
    -ms-animation: spinner 150ms infinite linear;
    -o-animation: spinner 150ms infinite linear;
    animation: spinner 150ms infinite linear;
    border-radius: 0.5em;
    -webkit-box-shadow: rgba(0, 0, 0, 0.75) 1.5em 0 0 0, rgba(0, 0, 0, 0.75) 1.1em 1.1em 0 0, rgba(0, 0, 0, 0.75) 0 1.5em 0 0, rgba(0, 0, 0, 0.75) -1.1em 1.1em 0 0, rgba(0, 0, 0, 0.5) -1.5em 0 0 0, rgba(0, 0, 0, 0.5) -1.1em -1.1em 0 0, rgba(0, 0, 0, 0.75) 0 -1.5em 0 0, rgba(0, 0, 0, 0.75) 1.1em -1.1em 0 0;
    box-shadow: rgba(0, 0, 0, 0.75) 1.5em 0 0 0, rgba(0, 0, 0, 0.75) 1.1em 1.1em 0 0, rgba(0, 0, 0, 0.75) 0 1.5em 0 0, rgba(0, 0, 0, 0.75) -1.1em 1.1em 0 0, rgba(0, 0, 0, 0.75) -1.5em 0 0 0, rgba(0, 0, 0, 0.75) -1.1em -1.1em 0 0, rgba(0, 0, 0, 0.75) 0 -1.5em 0 0, rgba(0, 0, 0, 0.75) 1.1em -1.1em 0 0;
}

/* Animation */

@-webkit-keyframes spinner {
    0% { -webkit-transform: rotate(0deg); -moz-transform: rotate(0deg); -ms-transform: rotate(0deg); -o-transform: rotate(0deg); transform: rotate(0deg); }
    100% { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); -o-transform: rotate(360deg); transform: rotate(360deg); }
}

@-moz-keyframes spinner {
    0% { -webkit-transform: rotate(0deg); -moz-transform: rotate(0deg); -ms-transform: rotate(0deg); -o-transform: rotate(0deg); transform: rotate(0deg); }
    100% { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); -o-transform: rotate(360deg); transform: rotate(360deg); }
}

@-o-keyframes spinner {
    0% { -webkit-transform: rotate(0deg); -moz-transform: rotate(0deg); -ms-transform: rotate(0deg); -o-transform: rotate(0deg); transform: rotate(0deg); }
    100% { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); -o-transform: rotate(360deg); transform: rotate(360deg); }
}

@keyframes spinner {
    0% { -webkit-transform: rotate(0deg); -moz-transform: rotate(0deg); -ms-transform: rotate(0deg); -o-transform: rotate(0deg); transform: rotate(0deg); }
    100% { -webkit-transform: rotate(360deg); -moz-transform: rotate(360deg); -ms-transform: rotate(360deg); -o-transform: rotate(360deg); transform: rotate(360deg); }
}