How to change interface font in css snippets?

Custom CSS & Theme Design
1

What I’m trying to do

i am trying to customize obsidian only using css snippets, and one thing that isn’t working rn is that i want to change the whole font between light and dark themes, but if i simply put to change the font in a

.theme-dark {
  --font-text: "JetBrains Mono"
}

.theme-light {
  --font-text: serif
}

it only changes the body of a note, not properties, nor does it change the mono spaced font or the interface font

besides this i want to added rounded corners like the AnuPpcuins theme and a full rainbow folder like it, but only for the light theme, either way, i can’t make sense of the infinity lines of repeating patterns of it
GitHub - AnubisNekhet/AnuPpuccin: Personal theme for Obsidian, i got the css here, but i can’t make it work

Things I have tried

i looked into the web a lot trying to understand css, but i am not sure what are the components that change these two things, i can only find body

thank you for reading this, any help is appreaciated

2

For the font question, you could add in the second two variables. e.g.

.theme-dark {
    --font-text: 'Comic Sans MS';
    --font-monospace-override: 'Victor Mono';
    --font-interface-override: 'Comic Sans MS';
}
3

thank you