Table Font size keeps reverting

I recently discovered and downloaded TablePress (so far, so good!) to make a simple table of content-type header. I have used the Plugin Options tab to adjust the font size of the text in my table:

.tablepress-id-3 tbody td {
font-family: Tahoma;
font-size: 10.5px;
}

I have adjusted the font size as I want it, and updated the tablepress-id # to the appropriate ID. But it doesn’t save. This should be ID-2 (not 3). I can manually change it to 2, save, open it and it looks great. But if I then use any of my other tables (I currently have 4), then the ID changes and the table looks awful.

I don’t know if the “save” will remain, but in this link, the ID should be “4”. It currently looks correct, now that I went in and updated it (from 3)
https://www.dantesdame.com/main/the-balkans-in-the-beginning

The page I need help with: [log in to see the link]