Tweak theme

themes/custom-theme/postcss.config.js

@@ -0,0 +1,39 @@
+const path = require("path");
+
+module.exports = () => ({
+  plugins: [
+    require("postcss-import")({
+      path: [
+        // Check for imports in <theme-dir>/css/assets
+        // TODO use Hugo's built-in inlineImports?
+        path.posix.join(__dirname, "assets", "css"),
+      ],
+    }),
+    require("postcss-url")([
+      {
+        filter: "**/typeface-*/files/*",
+        url: (asset) => {
+          // Construct font path relative to <publish-dir>/css/bundle.css
+          // Fonts must be mounted into static/ dir
+          return path.posix.join("/", "fonts", path.basename(asset.pathname));
+        },
+      },
+    ]),
+    require("postcss-nesting"),
+    require("postcss-custom-media"),
+    ...(process.env.HUGO_ENVIRONMENT === "production"
+      ? [
+          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"],
+          }),
+        ]
+      : []),
+  ],
+});