postcss -webkit and -moz not working

[l2zeo]

The settings are as follows.
The autoprefixer doesn't seem to work.
How can I do it?

postcss.config.js

const purgecss = require('@fullhuman/postcss-purgecss')
const cssnano = require('cssnano')

module.exports = {
  plugins: [
    require('tailwindcss')('./tailwind.config.js'),
    process.env.NODE_ENV === 'production' ? require('autoprefixer') : null,
    process.env.NODE_ENV === 'production' ? cssnano({ preset: 'default' }) : null,
    purgecss({
      content: ['./public_html/**/*.php', './src/**/*.vue', './src/**/*.jsx', './node_modules/tailwindcss-dark-mode/prefers-dark.js'],
      defaultExtractor: content => content.match(/[\w-:./]+(?<!:)/g) || []
    })
  ]
}

package.json

{
  "name": "site",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build:jquery": "cp node_modules/jquery/dist/jquery.slim.min.js public_html/build/js/",
    "build:custom": "postcss public_html/css/custom.css -o public_html/build/custom.css",
    "build:css": "postcss css/tailwind.css -o public_html/build/tailwind.css",
    "watch": "watch 'npm run build:custom & npm run build:css' public_html/build"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@fullhuman/postcss-purgecss": "^3.1.3",
    "@tkh/tailwind-plugin-flex-basis": "^1.4.0",
    "add": "^2.0.6",
    "autoprefixer": "^10.1.0",
    "cssnano": "^4.1.10",
    "express": "^4.17.1",
    "file-system": "^2.2.2",
    "https": "^1.0.0",
    "jquery": "^3.5.1",
    "mysql": "^2.18.1",
    "or": "^0.2.0",
    "postcss": "^8.2.2",
    "postcss-cli": "^8.3.1",
    "smelte": "^1.0.18",
    "socket.io": "^3.0.4",
    "tailwindcss": "^2.0.2",
    "tailwindcss-aspect-ratio": "^3.0.0",
    "watch": "^1.0.2",
    "yarn": "^1.22.10"
  },
  "devDependencies": {
    "tailwindcss-dark-mode": "^1.1.7",
    "tailwindcss-plugins": "^0.3.0"
  }
}

npm run watch