.overlay {
    position: relative;
}
.overlay::after {
    content: "";
    font-size:24px;
    color: black;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color:#000000;
    z-index: 999;
    /* IE 8 */
    -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=10)";
    /* IE 5-7 */
    filter: alpha(opacity=10);
    /* Netscape */
    -moz-opacity: 0.1;
    /* Safari 1.x */
    -khtml-opacity: 0.1;
    /* Good browsers */
    opacity: 0.1;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    border-radius: 5px;
}

.overlay::before {
    position: absolute;
    top: 50%;
    left: 50%;
    content: "\e031";
    display: inline-block;
    font-family: 'Glyphicons Halflings';
    font-style: normal;
    font-weight: 400;
    line-height: 1;
    text-rendering: auto;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    -webkit-animation: fa-spin 2s infinite linear;
    animation: fa-spin 2s infinite linear;
    font-size:36px;
    z-index: 1000;
}

/* overlay on inline form or single buttons should be smaller */
a.btn.overlay::before,
.btn-toolbar .form-inline-display.overlay::before {
    font-size: 12px;
}