Change "Date" Font Size In Different Places

I would like the Date Fonts to be different sizes for different places. Can you tell me please how I do this?

1. Date on Widget should be 12px (as it is now)
2. Date on Single Event page should be 16px

Example: https://christiangays.com/events/2017/03/wilton-manors-fl-3/

Thank you.
Support access is granted.