Jam calendar needs sticky header for Month + Date

[micheal-w-wells]

Is your feature request related to a problem? Please describe.
Page is simple and looks good, and titles staying to left as you scroll is great but it is definitely missing the month and date being a sticky header so they are always visible.

Describe the solution you'd like
position: sticky

Describe alternatives you've considered
Would be better than scrolling up.

Additional context
I did not see the jam calendar page source in itchio org but would consider taking a look if its here somewhere.