Hello,
Sorry, please change this code http://prntscr.com/go89x3 to:
.widget_product_categories.sidebar-widget ul .open-this:before, .wpb_widgetised_column .widget_product_categories ul .open-this:before, .widget_nav_menu.sidebar-widget ul .open-this:before { content: '\f0ab' !important; color: #000 !important; font-size: 30px !important; }
Regards
