PostCSS config for a legacy SASS project

postcss.config.js

module.exports = {
  parser: "postcss-scss",
  plugins: [
    require("postcss-easy-import")({        // Enables globs in @import. See style.css.
      prefix: false,
      skipDuplicates: false,
      warnOnEmpty: false,
    }),
    require("postcss-advanced-variables"),  // Sass-style @ vars, looping, and @import
    require("postcss-custom-media"),        // Custom reusable media queries
    require("postcss-nested"),              // Sass-style rule nesting
    require("postcss-preset-env") ({        // Automatically polyfill modern CSS features
      features: {
        "nesting-rules": false, // disables CSS nesting in favor of Sass-style nesting (postcss-nested)
      },
    }),
    require("postcss-pxtorem"),             // Converts units to rems (defaults to only font properties @ 16px base size)
    require("postcss-assets"),              // Filename resolver for images
    require('postcss-discard-comments'),    // Removes all comments (/* */)
  ],
};

Separate config from a non-SASS non-legacy project as reference for postcss-pxtorem
https://www.npmjs.com/package/postcss-pxtorem

module.exports = {
  plugins: {
    tailwindcss: {},
    autoprefixer: {},
    'postcss-pxtorem': {
      rootValue: 16,
      unitPrecision: 5,
      propList: [
        'font', 'font-size', 'line-height', 'letter-spacing',
        'margin*', 'padding*', 'max-*', 'min-*', 'gap*'
      ],
      selectorBlackList: [],
      replace: true,
      mediaQuery: true,
      minPixelValue: 0,
      exclude: /node_modules/i
    }, // Converts units to rems (defaults to only font properties @ 16px base size)
    ...(process.env.NODE_ENV === 'production' ? {cssnano: {}} : {})
  },
}

Example output:

@media (min-width: 75rem) {
  .min-\[1200px\]\:ml-\[10\%\] {
    margin-left: 10%
  }
}

@media (min-width: 80rem) {
  .xl\:max-w-\[260px\] {
    max-width: 16.25rem
  }
}

Note that apparently there is a newly maintained fork of postcss-pxtorem at https://github.com/hemengke1997/postcss-pxtorem