That CSS already uses an absolute font-size for the body element. That’s a no-go in this century – people have their preferred font size, and CSS authors should respect that by using 1em or 100%. Someone forcing 14px on me might have an otherwise brilliant CSS (which I doubt), but I’d discourage people from using this stuff.
Other things jumping into my face:
- two rules for
body - wildly inconsistent usage of absolute and relative units for margins and padding
- useless rules like
body>h1:first-childfollowing an identical rule forbody>*:first-child. Goodness. - This thing is presumably adapted for MMD composer version 4. Which was last updated about four years ago. Things have changed since then, notably with CSS.
I’m not saying that this CSS doesn’t work. But it is badly written and very, very out of date.
I can understand that you didn’t read through this mess. Just forget it and write your own one from scratch. That has the advantage that you won’t end up with a lot of useless crap and that you learn how CSS works. And you can use modern concepts like CSS variables, nested selectors, dark mode handling etc. to produce good CSS.