.popup {
    display: none;
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.5);
}

.popup-content {
    background-color: #fff;
    margin: 15% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    border-radius: 10px;
    text-align: center;
}

.close-btn {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
}

.close-btn:hover,
.close-btn:focus {
    color: #000;
    text-decoration: none;
    cursor: pointer;
}
.lds-dual-ring,
    .lds-dual-ring:after {
    box-sizing: border-box;
    }
    .lds-dual-ring {
    display: inline-block;
    width: 80px;
    height: 80px;
    }
    .lds-dual-ring:after {
    content: " ";
    display: block;
    width: 64px;
    height: 64px;
    margin: 8px;
    border-radius: 50%;
    border: 6.4px solid currentColor;
    border-color: currentColor transparent currentColor transparent;
    animation: lds-dual-ring 1.2s linear infinite;
    }
    @keyframes lds-dual-ring {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
    }