more cleanup

- removing all that is necessary

public/assets/js/postcss.js

-module.exports = {
-  use: [
-    'postcss-flexbugs-fixes',
-    'autoprefixer'
-  ],
-  map: false,
-  autoprefixer: {
-    browsers: [
-      //
-      // Official browser support policy:
-      // https://v4-alpha.getbootstrap.com/getting-started/browsers-devices/#supported-browsers
-      //
-      'Chrome >= 35', // Exact version number here is kinda arbitrary
-      // Rather than using Autoprefixer's native "Firefox ESR" version specifier string,
-      // we deliberately hardcode the number. This is to avoid unwittingly severely breaking the previous ESR in the event that:
-      // (a) we happen to ship a new Bootstrap release soon after the release of a new ESR,
-      //     such that folks haven't yet had a reasonable amount of time to upgrade; and
-      // (b) the new ESR has unprefixed CSS properties/values whose absence would severely break webpages
-      //     (e.g. `box-sizing`, as opposed to `background: linear-gradient(...)`).
-      //     Since they've been unprefixed, Autoprefixer will stop prefixing them,
-      //     thus causing them to not work in the previous ESR (where the prefixes were required).
-      'Firefox >= 38', // Current Firefox Extended Support Release (ESR); https://www.mozilla.org/en-US/firefox/organizations/faq/
-      // Note: Edge versions in Autoprefixer & Can I Use refer to the EdgeHTML rendering engine version,
-      // NOT the Edge app version shown in Edge's "About" screen.
-      // For example, at the time of writing, Edge 20 on an up-to-date system uses EdgeHTML 12.
-      // See also https://github.com/Fyrd/caniuse/issues/1928
-      'Edge >= 12',
-      'Explorer >= 9',
-      // Out of leniency, we prefix these 1 version further back than the official policy.
-      'iOS >= 8',
-      'Safari >= 8',
-      // The following remain NOT officially supported, but we're lenient and include their prefixes to avoid severely breaking in them.
-      'Android 2.3',
-      'Android >= 4',
-      'Opera >= 12'
-    ]
-  }
-}