Hello Kristi,
I agree, the first screenshot calendar looks pretty snazzy! As much as I would love to help, theme support/customizations are out of our hands :-/
I’d probably start by reviewing our Themer’s Guide and see if you’re able to get started in the right direction. One other idea would be to visit the site of the screenshot provided and right-click on your mouse and open “Inspect”. From there, you can identify some CSS and maybe get a little more insight on how they’re going about it.
I hope this helps and thanks for reaching out. Take care!