.modal {
    display: none;
    /* Hidden by default */
    position: fixed;
    /* Stay in place */
    z-index: 1;
    /* Sit on top */
    left: 0;
    top: 0;
    width: 100%;
    /* Full width */
    height: 100%;
    /* Full height */
    overflow: auto;
    /* Enable scroll if needed */
    background-color: rgb(0, 0, 0);
    /* Fallback color */
    background-color: rgba(0, 0, 0, 0.4);
    /* Black w/ opacity */
}

.modal-content {
    position: relative;
    background-color: #fefefe;
    margin: auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 300px;
    /* Could be more or less, depending on screen size */
    text-align: center;
}

.loader {
    border: 16px solid #f3f3f3;
    /* Light grey */
    border-top: 16px solid #3498db;
    /* Blue */
    border-radius: 50%;
    width: 120px;
    height: 120px;
    animation: spin 2s linear infinite;
    margin: auto;
}

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