I checked it out but couldn't figure out how to add my own color schemes? I'd preferably be able to use base16 flat https://chriskempson.github.io/base16/#flat

I checked it out but couldn't figure out how to add my own color schemes? I'd preferably be able to use base16 flat https://chriskempson.github.io/base16/#flat https://chriskempson.github.io/base16/#flat however I can't even find a way to manually add color values.