I can't remember for sure, but I believe that notification bar was on a "to-watch-later" or "to-do-later" list when developing the theme and didn't get styled because this is a single bar that it's used in many other different places and its behavior varies depending on what sort of notification is being displayed on it at that time. So that was something to jenga with, hence why it was on that list.
That being said. If this is a notification bar to show only for new users, I believe you can add this code below and do a more precise targeting , specifically for that type of notification only.
background-color: rgba(0, 0, 0, 0.7);
font-family: 'Material Icons';
Now I can't see this bar when accessing your website so there's no way of precisely debug this. But if this is a different kind of bar... You can swap the first line where "#notice_visitor" is to ".qa-notice" instead. But what this will do is target all the notification bars that have that same element targeting, so I really don't know how this would play off in terms of affecting all the other notification bars there might be around your website. So I'd not recommend doing this. But if you really really really want that bar to be showed is up to you.
I'd personally just move the information to the sidebar box if my only option was the second choice. Thanks for the feedback, this information will be saved.