system allows the start date and end date modals to be open at the same time. when they are, they overlap.
Also, if you click just to open the end date modal, it coves up the start date, which is not good. as a short term fix perhaps we do the following:
1. open the modals BELOW the top bar that contains the "click to add start date" and "click to add end date" buttons, so they don't cover up any dates
2. don't allow the start date and end date modals to be open at the same time.