visibility of dates in calendar

Hi,

I love this plugin but I find it hard to see the dates and times I’m choosing in the pop-up calendars. When I click to edit a time, the time slots are all on a light gray background with white text, I have to guess at what each time slot is.

I tried adjusting my wordpress user colour settings but it did not affect the a colours used in the plugin.

Is there anyway to adjust these colours?