Using the default theme, in ordered lists, the numbers are the same shade of gray in both the dark and light color schemes. But in the dark scheme, they’re much too dark to see clearly, and much darker than the bullets:
How can I control the color of the numbers? I searched the Obsidian Discord, but found nothing that helps.
The complete list of all CSS settings is a massive list, and since in addition it can be combined for various special cases, it’s even more gigantous.
Your best bet is to get familiar with the Developer Tools, and navigating the elements to locate what you want to change. In addition you can look at various CSS files connected to themes, or the default theme. But it’s a massive endeavour to try to get an overview of all the possible settings.