Custom CSS in Appointments+ Not Working

I am making a simple CSS edit in Appointments+ but it is not working because it is inserting it above your code. Custom Stylesheets need to add code at the bottom or they are ineffective could you please fix this...

Example: I am trying to simply change the background color of the appointment calendar cells which is done with:

background: #48c048 !important;

background: #FFEF00 !important;

PROBLEM: Your code is on line 146 when I use your "Additional css Rules" it is putting my code on line 144 which will not get the job done.
I can do this manually and I will but I shouldn't have to do this. Please fix it.