<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script>
    $(function() {
        $('.dwqa-container a[href]').attr('target', '_blank');
    });
</script>

2/ you can add the following code to the style.css file:

@media (max-width: 480px) {
.dwqa-single-question .wp-embed {
   width: 50%;
}
}

3/ I think it’s some issue come from the cache site or conflict the plugin.
4/ It’s default of the plugin when you select the best answer it will refresh not vote answer.

Please help and thanks in advance

request you to please consider this fix in your next update.