Changing Calendar Colors

Hello :) These are what the colors on my calendar are... 
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​Personally, I feel as though it would make more sense if my period days were red, and my fertile days were green. I sometimes find myself mistaking the red for the pink, as they are both fairly similar colors. If my calendar was marked with colors that made sense to me, I'm sure I would be able to comprehend my calendar quicker and easier. 
​That being said, my suggestion is to allow users to choose what color they want to mark their period, fertile, and regular days. This could be an option in the Settings.