Hi, Audra!
I can help with this! What are you seeing when you use the Skeleton Styles? When I have twenty sixteen activated with the Skeleton Styles I see the select box as well as the list you mention.

I did a quick mockup using the ‘Extra CSS’ option in the Customizer to hopefully show you a starting point. You can see the result of that below:

I suspect that if you’re seeing something different that the Tribe Bar is inheriting some styles from your theme. That’s not unexpected and it’s something we try to allow to happen when it can so that the Calendar matches your theme as much as it can. If your theme styles are being inherited you’ll just need to overwrite those.
I’d recommend moving the files to your theme directory before doing the customization, that way they won’t be overwritten during your next upgrade. You can find out more about that in our themer’s guide here: https://theeventscalendar.com/knowledgebase/themers-guide/
The files you’ll be most interested in are
- the-events-calendar/src/views/modules/bar.php and
- the-events-calendar/src/resources/css/tribe-events-skeleton.css
I hope this answers your question! Let me know how it goes 🙂
Cheers,
Trisha