@AbramBaileyAuD I have designed websites in the past. I have no real issues with creating the necessary code for the text content, navigation, php server responses etc. That side I don't mind as it's all purely technical.
However, I absolutely hate dealing with css. The difficulty is more to do with deciding what font, what colour, what size, left, middle, right, how does it contrast with header, footer, another section, aligning images etc. Then you throw in accessibility and discover that your nice new blue heading font is technically not accessible in terms of sufficient contrast.
I swore that I would never work in website design. I find it very frustrating and it just drains you of all energy as you are constantly tweaking the "look" and it never ends.
Interesting irony, the spacing of the text on my website is pretty much the same as yours and I have only just realised that today because I am updating my website! Although my font is fractionally smaller.
So, I honestly would not sweat the CSS stuff. It can end up being a massive time drain for very little benefit I have discovered. I just don't enjoy doing anything with CSS as there are better things to do with one's life! I would rather work on api's and dealing with actual data and content, not with css design.
As long as people can read the text with sufficient contrast and the page does not look too busy, I would say problem is solved. The important thing to focus on is why you changed the forum to the new one in the first place and I suspect that had more to do with manipulation of data, categorisation etc.