[1]

css-modules/css-modules: Documentation about css-modules ( (2017-02-06 00:15:05 +09:00)) https://github.com/css-modules/css-modules

A CSS Module is a CSS file in which all class names and animation names are scoped locally by default. All URLs (url(...)) and @imports are in module request format (./xxx and ../xxx means relative, xxx and xxx/yyy means in modules folder, i. e. in node_modules).

[2] Web標準の CSS とは異なる別のスタイルシート言語です。