You have helped me identify the issue. I appreciate all the help from yourself and everyone. The issue was as you mentioned, me not targeting a specific block with CSS as opposed to all the tables (including the calendar) showing the lines i targeted with my code. Thank you so much.
The website isn't private, it is live, the page however isn't accessible from the website yet and is hidden. The page is: https://teamkreve.com/calendar
Let me know if this works? Thanks