.overlay{
    opacity:0.4;
    background-color:#ccc;
    position:fixed;
    width:100%;
    height:100%;
    top:0px;
    left:0px;
    z-index:1000;
}

.spinner {
    border: 16px solid #f3f3f3;
    border-top: 16px solid #838383;
    border-radius: 50%;
    width: 90px;
    height: 90px;
    animation: spin 2s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}