Added PostCSS to reduce size of CSS

.gitignore

@@ -2,3 +2,4 @@
 .hugo_build.lock
 resources/
 public/
+node_modules/

layouts/partials/head.html

@@ -19,10 +19,15 @@
 <!-- CSS -->
 {{ $options := (dict "targetPath" "main.css" "outputStyle" "compressed" "enableSourceMap" true) }} 
 {{ $style := resources.Get "scss/main.scss" | resources.ToCSS $options }}
+
+{{ if hugo.IsProduction }}
+  {{ $style = $style | resources.PostCSS | resources.Fingerprint "sha256" }}
+{{ end }}
+
 <link rel="stylesheet" href="{{ $style.RelPermalink }}" />
 
 {{ range $val := $.Site.Params.customCSS }} {{ if gt (len $val) 0 }}
-<link rel="stylesheet" type="text/css" href="{{ $val }}" />
+<link rel="stylesheet" type="text/css" href="{{ $val }}" integrity="{{ $style.Data.Integrity }}" />
 {{ end }} 
 {{ end }}
 

layouts/partials/javascript.html

@@ -1,6 +1,6 @@
 {{ $bootstrap := resources.Get "js/bootstrap.bundle.min.js" }}
-{{ $secureJS := slice $bootstrap | resources.Concat "bundle.js" | resources.Minify }}
-<script src="{{ $secureJS.RelPermalink }}"></script>
+{{ $secureJS := slice $bootstrap | resources.Concat "bundle.js" | resources.Minify | resources.Fingerprint "sha512" }}
+<script src="{{ $secureJS.RelPermalink }}" integrity="{{ $secureJS.Data.Integrity }}"></script>
 
 {{ range $val := $.Site.Params.customJS }}
 {{ if gt (len $val) 0 }}

package.json

@@ -0,0 +1,7 @@
+{
+  "dependencies": {
+    "@fullhuman/postcss-purgecss": "^4.1.3",
+    "postcss": "^8.4.14",
+    "postcss-cli": "^10.0.0"
+  }
+}

postcss.config.js

@@ -0,0 +1,13 @@
+module.exports = {
+  plugins: {
+    "@fullhuman/postcss-purgecss": {
+      content: [
+        "./assets/js/*.js",
+        "./content/*.md",
+        "./layouts/**/*.html",
+      ],
+      safelist: ["arrow", "tooltip", "tooltip-arrow", "tooltip-inner"],
+      blocklist: [""],
+    },
+  },
+};