Org mode by default just uses your user agent stylesheet. Adding some CSS is trivial, so just write your own damn styles instead of adding a sandyuraz.com dependency for no reason.
Author here! I’m not the biggest fan of having thousands and thousands of external dependencies. I’m not too big on frontend but I have been using org mode for couple of years now. Just wanted to share some small adjustments one can make to make results prettier!
If I made one for myself, literally anyone can copy it or make their own to their style
I would be supportive if the advice is “copy those styles, extend them or host it themselves”, not adding a dependency that’s bound to be broken sooner or later. There are way too many bloated, slow, or broken websites due to linking to random blurbs from the internet.
Adding interactivity on the other hand is more involved. I recommend org-info-js which is what I use with my journals. https://orgmode.org/manual/JavaScript-support.html