.lds-dual-ring.hidden {
        display: none;
    }
 
.overlay {
    width: 100%;
    height: 100vh;
    z-index: 999;
    opacity: 1;
    transition: all 0.5s;
}
     
.lds-dual-ring {
    display: inline-block;
    width: 80px;
    height: 80px;
}
.lds-dual-ring:after {
    content: " ";
    display: block;
    width: 64px;
    height: 64px;
    margin: 5% auto;
    border-radius: 50%;
    border: 6px solid black;
    border-color: black transparent black transparent;
    animation: lds-dual-ring 1.2s linear infinite;
}
.lds-center {
    margin-left: auto; 
    margin-right: auto; 
    display: table;
}
@keyframes lds-dual-ring {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}