This is the universal color pallette that exists in the Untitled UI design kit. The format for these class names is ui-[slugified-color]-[shade]. All of these are customizable per-site via CSS variables.
Colors
ui-base
ui-gray-light-mode
ui-gray-blue
ui-gray-cool
ui-gray-modern
ui-gray-neutral
ui-brand
ui-error
ui-warning
ui-success
ui-green
ui-gray-iron
ui-gray-true
ui-gray-warm
ui-moss
ui-green-light
ui-teal
ui-cyan
ui-blue-light
ui-blue
ui-blue-dark
ui-indigo
ui-violet
ui-purple
ui-fuchsia
ui-pink
ui-rose
ui-orange-dark
ui-orange
ui-yellow
ui-gray-dark-mode-alpha
ui-gray-dark-mode
Generating colors from Untitled UI
From time to time standard set of colors may change, do not fear updating
them is (kinda) easy.