CLI

The nemcss CLI provides standalone build, watch, init, and schema commands. No build tool required.

Installation

npm

npm install -D nemcss

pnpm

pnpm add -D nemcss

yarn

yarn add -D nemcss

bun

bun add -D nemcss

global

npm install -g nemcss

When installed locally, run commands via npx nemcss <command> or add them as scripts in your package.json.

Commands

Command	Description
nemcss init	Scaffold nemcss.config.json and example token files in the current directory
nemcss build -i <input> -o <output>	One-shot build: scan content files and write CSS
nemcss watch -i <input> -o <output>	Watch mode: rebuild on token, content, or config changes
nemcss schema	Print the JSON schema for nemcss.config.json to stdout

init

npx

npx nemcss init

pnpm dlx

pnpm dlx nemcss init

yarn dlx

yarn dlx nemcss init

global / local

nemcss init

build

nemcss build -i src/styles.css -o dist/styles.css

watch

nemcss watch -i src/styles.css -o dist/styles.css

schema

Prints the JSON schema for nemcss.config.json to stdout. Useful for piping into a file or validating the schema shape.

nemcss schema > nemcss.config.schema.json

Directives

The CLI looks for two directives in the input file and replaces them with generated CSS:

Directive	Output
@nemcss base;	:root { --custom-properties }
@nemcss utilities;	Utility classes + responsive media queries

The @nemcss utilities directive is optional. The CLI exits with an error if the @nemcss base directive is not found in the input file as it is the one responsible for injecting the custom properties derived fom the design tokens.

/* Use both together */
@nemcss base;
@nemcss utilities;

/* Or scope to cascade layers */
@layer tokens, utilities;

@layer tokens {
  @nemcss base;
}

@layer utilities {
  @nemcss utilities;
}

Configuration

A minimal nemcss.config.json:

{
  "content": ["src/**/*.html", "src/**/*.tsx"],
  "tokensDir": "design-tokens"
}

See the full configuration reference.