.lds-dual-ring {
    display: inline-block;
    width: 180px;
    height: 180px;
    position: fixed;
    z-index: 999;
    overflow: hidden;
    margin: auto;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    display:none;
}

    .lds-dual-ring:after {
        content: " ";
        display: block;
        width: 164px;
        height: 164px;
        margin: 8px;
        border-radius: 50%;
        border: 6px solid #00ff21;
        border-color: #00ff21 transparent #00ff21 transparent;
        animation: lds-dual-ring 1.5s linear infinite;
    }

@keyframes lds-dual-ring {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}