Hi,  I would like to ask if it's possible to change the colour of the dates on our calendar when we are closed (Sunday, Monday & Tuesday). I am using the older version and if I update it, the css codes which was implemented by our designer will be gone. (I have tried that). Is there anyway I can change the colour of the unavailable dates without updating by only adding some scripts to the css files? if the answer is yes, could you please let me know which file is it and what css code do I need to add/change?  Many thanks. here is the website:  https://mypureaesthetics.com/online-booking/