number sections and document sidebar ordering

docs/content/03-customization/index.md

@@ -0,0 +1,3 @@
+# Customizing Your Site
+
+Site settings live in `config.yaml`. You can change the title, logo, colors, and enable features like analytics or multi-language support.

docs/content/03-customization/plugins.md

@@ -0,0 +1,13 @@
+# Writing Plugins
+
+Create JavaScript modules in the `plugins/` directory. Export hook functions such as `onParseMarkdown` or `onPageRendered` to modify the build.
+
+Example:
+
+```js
+module.exports = {
+  onPageRendered: async ({ html }) => {
+    return { html: html + '\n<!-- custom -->' };
+  }
+};
+```