arc-plugin-lightningcss v0.0.1-alpha.1

npm i --save-dev arc-plugin-lightningcss

#...

@plugins
arc-plugin-lightningcss

# optional config
@lightningcss
targets '>= 0.25%' # default
input src/css/style.css # default
output public/style.css # default

# add output to your .gitignore
public/style.css