css-loader——translates CSS into CommonJS
The css-loader interprets @import and url() like import/require() and will resolve them.
style-loader——creates style nodes from JS strings
Adds CSS to the DOM by injecting a <style> tag
sass-loader——compiles Sass to CSS, using Node Sass by default
Loads a Sass/SCSS file and compiles it to CSS. Use the css-loader or the raw-loader to turn it into a JS module and the MiniCssExtractPlugin to extract it into a separate file.