Hey Meghan,
Thanks for reaching out!
These sorts of questions are unfortunately ones we cannot help with 🙁 Read more about this fact on this page ? https://theeventscalendar.com/knowledgebase/what-support-is-provided-for-license-holders/
To write custom CSS on your site, definitely check out a [free!] tool like Firebug if you use FireFox, or the Developer Tools for either Safari or Chrome. They have “Inspector” tools that let you zoom right over the element whose styles you want to change.
As a quick example to hopefully help you get started in the right direction here, you might find that this bit of CSS helps to make the day number text white:
span.list-daynumber {
color: #fff !important;
}
I hope that helps! If not right away, tinker a bit using the tools and methods I shared above to get the CSS to apply.
Best of luck with your customizations!
George