function twitterfix() {

     if(typeof $("#twitter-widget-0").contents().find(".load-more").html() == 'undefined') {
          setTimeout(twitterfix, 500);
     }
     else {
          var head = $("#twitter-widget-0").contents().find("head");
          head.append('<link type="text/css" rel="stylesheet" href="wp-content/themes/mywordpresstheme/style.css">');
          head.append('<style>.h-entry.tweet.with-expansion.customisable-border {border-bottom: 1px solid #EFEEEE;}</style>');
     }
}

$(document).ready(function () {

     twitterfix();

});