tailwindcss/integrations/webpack-4/webpack.config.js

let MiniCssExtractPlugin = require('mini-css-extract-plugin')

module.exports = {
  plugins: [new MiniCssExtractPlugin()],
  module: {
    rules: [
      {
        test: /\.css$/i,
        use: [MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader'],
      },
    ],
  },
}