I am trying to change the background color of cells on a full calendar, regardless of whether there is an event that shares the cell. I have availability data for different times and would like to display a heatmap on my FullCalendar of member availability, a little like a when2meet. I have attempted to do this with uneditable background events without titles, but their background color does not match what I put the background color as (for example, if I set color for a background to "#000000" it displays as light gray).
Is there either a way to add classes to certain time slot cells (for example 8-8:30 on x date) so I can edit their css or to make background color for background events display correctly?