Changing highlight color on upcoming event in upcoming calendar widget

I would like to change the color of the event date in the upcoming calendar widget as I can't see a difference and don't even know if there is a date scheduled.

I found 2 threads that addressed this, tried the css on the one thread and it did not work. There is no answer on the other one.
https://premium.wpmudev.org/forums/topic/is-there-a-way-to-make-the-highlight-on-the-calendar-widget-darker

https://premium.wpmudev.org/forums/topic/were-can-i-change-the-color-of-the-calendar-upcoming-widget

Here is page to show you with a calendar entry for March 4, 2017 so you can see the problem:
http://www.rmsatemp.com/schedule-of-events-by-location/

I refer to the calendar widget and the color I want March 4th to be is #dd3333

However, I want this to apply to any date that is listed. I have also enabled support access and thanks in advance for your help. Linda iempoweru