Expanded Palette
The default color palette is color_expanded.css and consists of ten colors, eight of which have nine stops; gray, red, pink, purple, blue, green, yellow, orange. Yin (black) has ten stops while yang (white) only has one stop.
If you want more granularity (read: opacity), you can call the raw version of the color (append -raw to the variable name) which will return the OKLCH values so you can do something like this: oklch(var(--uchu-gray-1-raw) / 40%).
Gray

var(--uchu-gray-1)var(--uchu-gray-2)var(--uchu-gray-3)var(--uchu-gray-4)var(--uchu-gray-5)var(--uchu-gray-6)var(--uchu-gray-7)var(--uchu-gray-8)var(--uchu-gray-9)
Red

var(--uchu-red-1)var(--uchu-red-2)var(--uchu-red-3)var(--uchu-red-4)var(--uchu-red-5)var(--uchu-red-6)var(--uchu-red-7)var(--uchu-red-8)var(--uchu-red-9)
Pink

var(--uchu-pink-1)var(--uchu-pink-2)var(--uchu-pink-3)var(--uchu-pink-4)var(--uchu-pink-5)var(--uchu-pink-6)var(--uchu-pink-7)var(--uchu-pink-8)var(--uchu-pink-9)
Purple

var(--uchu-purple-1)var(--uchu-purple-2)var(--uchu-purple-3)var(--uchu-purple-4)var(--uchu-purple-5)var(--uchu-purple-6)var(--uchu-purple-7)var(--uchu-purple-8)var(--uchu-purple-9)
Blue

var(--uchu-blue-1)var(--uchu-blue-2)var(--uchu-blue-3)var(--uchu-blue-4)var(--uchu-blue-5)var(--uchu-blue-6)var(--uchu-blue-7)var(--uchu-blue-8)var(--uchu-blue-9)
Green

var(--uchu-green-1)var(--uchu-green-2)var(--uchu-green-3)var(--uchu-green-4)var(--uchu-green-5)var(--uchu-green-6)var(--uchu-green-7)var(--uchu-green-8)var(--uchu-green-9)
Yellow

var(--uchu-yellow-1)var(--uchu-yellow-2)var(--uchu-yellow-3)var(--uchu-yellow-4)var(--uchu-yellow-5)var(--uchu-yellow-6)var(--uchu-yellow-7)var(--uchu-yellow-8)var(--uchu-yellow-9)
Orange

var(--uchu-orange-1)var(--uchu-orange-2)var(--uchu-orange-3)var(--uchu-orange-4)var(--uchu-orange-5)var(--uchu-orange-6)var(--uchu-orange-7)var(--uchu-orange-8)var(--uchu-orange-9)
General

var(--uchu-yin-1)var(--uchu-yin-2)var(--uchu-yin-3)var(--uchu-yin-4)var(--uchu-yin-5)var(--uchu-yin-6)var(--uchu-yin-7)var(--uchu-yin-8)var(--uchu-yin-9)var(--uchu-yin)var(--uchu-yang)
Sass
If you know what Sass is, you'll know how to use color_expanded.scss. I didn't provide raw versions of them because Sass comes with so many color tools (and, I've been using regular CSS variables in my Sass anyways).
JS
If you are a fan of CSS-in-JS or need to programmatically grab color values, there's color.json and color.ts includes available.