Change Calendar Picker Color?



I looked through the OmniFocusColors app but couldn’t find an item that seemed like it matched, so I figured I would ask here. I am using the default dark theme which I quite like, but I cannot stand the color choice for the calendar picker/popup when assigning due/defer dates. The current months days are almost the same exact color as the background, whereas days from other months are perfectly legible. This seems entirely backward to me! (See here for an example of what I am talking about)

Is there a way to change this? What is the item in Colors that controls this?