Fix postcss

themes/hugo-theme-gruvbox/postcss.config.js

@@ -25,6 +25,14 @@ module.exports = () => ({
       ? [
           require("postcss-preset-env"),
           require("cssnano"),
+          require("@fullhuman/postcss-purgecss")({
+            content: ["./hugo_stats.json"],
+            defaultExtractor: (content) => {
+              let els = JSON.parse(content).htmlElements;
+              return els.tags.concat(els.classes, els.ids);
+            },
+            safelist: ["data-theme"],
+          }),
         ]
       : []),
   ],