#wp-admin-bar-custom-regenerate-cache-button .loading-spinner {
    display: none;
    border: 4px solid rgb(167, 165, 165);
    border-radius: 50%;
    border-top: 4px solid #ffffff;
    width: 16px;
    height: 16px;
    animation: spin 1s linear infinite;
    margin-left: 8px;
}

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

#wp-admin-bar-custom-regenerate-cache-button.loading .loading-spinner {
    display: inline-block;
}