Hi Laura,
Thanks so much for reaching out!
Just to let you know, we are limited by our Support Policy in how much we can help with customizations, but I will try to point you in the right direction.
As a first step, you may want to take a look at your stylesheets and page templates that you have set up, as those can dictate how much of the styling is pulled from your theme:
https://theeventscalendar.com/knowledgebase/stylesheets-and-page-templates/
Secondly, you may want to take a look at our Themer’s Guide, which can help you with modifying our templates. You will probably just need to modify the stylesheet in this case, but you may also want to take a look at the single-event.php template.
If this functionality is a requirement for your intended project, I’d suggest that a third-party developer would be the best way to make this feature happen on a short timeline. ? We maintain a list of developers who work with our plugins on our Knowledgebase here:
https://theeventscalendar.com/knowledgebase/find-a-customizer/
Let me know if you have further questions along the way!
Thanks,
Jaime