Ignore generated content/ output and erl_crash.dump

- Add flake.nix dev shell with Node.js 22, Elixir, and Emacs+ox-hugo
- Add scripts/export.exs: exports org-roam notes to content/ via ox-hugo,
  mirroring subdirectory structure and generating a fallback index.md
- Add npm scripts: export, build:notes, serve:notes
- Configure FrontMatter plugin for TOML (ox-hugo default output)
- Replace ObsidianFlavoredMarkdown with OxHugoFlavouredMarkdown
- Add example notes: Madrid public transport (metro, bus, roads)
- Update README and AGENTS.md with org-roam workflow instructions

.gitignore

@@ -9,3 +9,7 @@ tsconfig.tsbuildinfo
 private/
 .replit
 replit.nix
+erl_crash.dump
+# content/ is generated by the export script; only keep the placeholder
+content/*
+!content/.gitkeep

AGENTS.md

@@ -0,0 +1,282 @@
+# AGENTS.md - Coding Agent Instructions
+
+This document provides essential information for AI coding agents working in this repository.
+
+## Project Overview
+
+**Quartz** is a static site generator for publishing digital gardens and notes as websites.
+Built with TypeScript, Preact, and unified/remark/rehype for markdown processing.
+
+| Stack         | Technology                                |
+| ------------- | ----------------------------------------- |
+| Language      | TypeScript 5.x (strict mode)              |
+| Runtime       | Node.js >=22 (v22.16.0 pinned)            |
+| Package Mgr   | npm >=10.9.2                              |
+| Module System | ES Modules (`"type": "module"`)           |
+| UI Framework  | Preact 10.x (JSX with `react-jsx` pragma) |
+| Build Tool    | esbuild                                   |
+| Styling       | SCSS via esbuild-sass-plugin              |
+
+## Environment
+
+This is a Nix project. Use the provided `flake.nix` to enter a dev shell with Node.js 22 and npm:
+
+```bash
+nix develop
+```
+
+All `npm` commands below must be run inside the dev shell.
+
+## Build, Lint, and Test Commands
+
+```bash
+# Type check and format check (CI validation)
+npm run check
+
+# Auto-format code with Prettier
+npm run format
+
+# Run all tests
+npm run test
+
+# Run a single test file
+npx tsx --test quartz/util/path.test.ts
+
+# Run tests matching a pattern (use --test-name-pattern)
+npx tsx --test --test-name-pattern="typeguards" quartz/util/path.test.ts
+
+# Build the static site
+npx quartz build
+
+# Build and serve with hot reload
+npx quartz build --serve
+
+# Profile build performance
+npm run profile
+```
+
+### Test Files Location
+
+Tests use Node.js native test runner via `tsx`. Test files follow the `*.test.ts` pattern:
+
+- `quartz/util/path.test.ts`
+- `quartz/util/fileTrie.test.ts`
+- `quartz/components/scripts/search.test.ts`
+
+## Code Style Guidelines
+
+### Prettier Configuration (`.prettierrc`)
+
+```json
+{
+  "printWidth": 100,
+  "tabWidth": 2,
+  "semi": false,
+  "trailingComma": "all",
+  "quoteProps": "as-needed"
+}
+```
+
+**No ESLint** - only Prettier for formatting. Run `npm run format` before committing.
+
+### TypeScript Configuration
+
+- **Strict mode enabled** (`strict: true`)
+- `noUnusedLocals: true` - no unused variables
+- `noUnusedParameters: true` - no unused function parameters
+- JSX configured for Preact (`jsxImportSource: "preact"`)
+
+### Import Conventions
+
+```typescript
+// 1. External packages first
+import { PluggableList } from "unified"
+import { visit } from "unist-util-visit"
+
+// 2. Internal utilities/types (relative paths)
+import { QuartzTransformerPlugin } from "../types"
+import { FilePath, slugifyFilePath } from "../../util/path"
+import { i18n } from "../../i18n"
+```
+
+### Naming Conventions
+
+| Element          | Convention   | Example                             |
+| ---------------- | ------------ | ----------------------------------- |
+| Files (utils)    | camelCase    | `path.ts`, `fileTrie.ts`            |
+| Files (comps)    | PascalCase   | `TableOfContents.tsx`, `Search.tsx` |
+| Types/Interfaces | PascalCase   | `QuartzComponent`, `FullSlug`       |
+| Type Guards      | `is*` prefix | `isFilePath()`, `isFullSlug()`      |
+| Constants        | UPPER_CASE   | `QUARTZ`, `UPSTREAM_NAME`           |
+| Options types    | `Options`    | `interface Options { ... }`         |
+
+### Branded Types Pattern
+
+This codebase uses branded types for type-safe path handling:
+
+```typescript
+type SlugLike<T> = string & { __brand: T }
+export type FilePath = SlugLike<"filepath">
+export type FullSlug = SlugLike<"full">
+export type SimpleSlug = SlugLike<"simple">
+
+// Always validate with type guards before using
+export function isFilePath(s: string): s is FilePath { ... }
+```
+
+### Component Pattern (Preact)
+
+Components use a factory function pattern with attached static properties:
+
+```typescript
+export default ((userOpts?: Partial<Options>) => {
+  const opts: Options = { ...defaultOptions, ...userOpts }
+
+  const ComponentName: QuartzComponent = ({ cfg, displayClass }: QuartzComponentProps) => {
+    return <div class={classNames(displayClass, "component-name")}>...</div>
+  }
+
+  ComponentName.css = style           // SCSS styles
+  ComponentName.afterDOMLoaded = script  // Client-side JS
+  return ComponentName
+}) satisfies QuartzComponentConstructor
+```
+
+### Plugin Pattern
+
+Three plugin types: transformers, filters, and emitters.
+
+```typescript
+export const PluginName: QuartzTransformerPlugin<Partial<Options>> = (userOpts) => {
+  const opts = { ...defaultOptions, ...userOpts }
+  return {
+    name: "PluginName",
+    markdownPlugins(ctx) { return [...] },
+    htmlPlugins(ctx) { return [...] },
+    externalResources(ctx) { return { js: [], css: [] } },
+  }
+}
+```
+
+### Testing Pattern
+
+Use Node.js native test runner with `assert`:
+
+```typescript
+import test, { describe, beforeEach } from "node:test"
+import assert from "node:assert"
+
+describe("FeatureName", () => {
+  test("should do something", () => {
+    assert.strictEqual(actual, expected)
+    assert.deepStrictEqual(actualObj, expectedObj)
+    assert(condition) // truthy assertion
+    assert(!condition) // falsy assertion
+  })
+})
+```
+
+### Error Handling
+
+- Use `try/catch` for critical operations (file I/O, parsing)
+- Custom `trace` utility for error reporting with stack traces
+- `process.exit(1)` for fatal errors
+- `console.warn()` for non-fatal issues
+
+### Async Patterns
+
+- Prefer `async/await` over raw promises
+- Use async generators (`async *emit()`) for streaming file output
+- Use `async-mutex` for concurrent build protection
+
+## Project Structure
+
+```
+quartz/
+├── bootstrap-cli.mjs    # CLI entry point
+├── build.ts             # Build orchestration
+├── cfg.ts               # Configuration types
+├── components/          # Preact UI components
+│   ├── *.tsx            # Components
+│   ├── scripts/         # Client-side scripts (*.inline.ts)
+│   └── styles/          # Component SCSS
+├── plugins/
+│   ├── transformers/    # Markdown AST transformers
+│   ├── filters/         # Content filters
+│   ├── emitters/        # Output generators
+│   └── types.ts         # Plugin type definitions
+├── processors/          # Build pipeline (parse/filter/emit)
+├── util/                # Utility functions
+└── i18n/                # Internationalization (30+ locales)
+```
+
+## Branch Workflow
+
+This is a fork of [jackyzha0/quartz](https://github.com/jackyzha0/quartz) with org-roam customizations.
+
+| Branch      | Purpose                                          |
+| ----------- | ------------------------------------------------ |
+| `main`      | Clean mirror of upstream quartz — no custom code |
+| `org-roam`  | Default branch — all customizations live here    |
+| `feature/*` | Short-lived branches off `org-roam`              |
+
+### Pulling Upstream Updates
+
+```bash
+git checkout main
+git fetch upstream
+git merge upstream/main
+git checkout org-roam
+git merge main
+# Resolve conflicts if any, then commit
+```
+
+### Working on Features
+
+```bash
+git checkout org-roam
+git checkout -b feature/my-feature
+# ... work ...
+git checkout org-roam
+git merge feature/my-feature
+git branch -d feature/my-feature
+```
+
+**Merge direction:** `upstream → main → org-roam → feature/*`
+
+## Org-Roam Workflow
+
+Notes live in a **separate directory** outside this repo. The export script
+converts them to Markdown via ox-hugo, then Quartz builds the site.
+
+### Tooling
+
+The dev shell (`nix develop`) provides:
+
+- `nodejs_22` — Quartz build
+- `elixir` — runs the export script
+- `emacs` + `ox-hugo` — performs the org → markdown conversion
+
+### Export and build
+
+```bash
+# Export only (wipes content/, exports all .org files)
+NOTES_DIR=/path/to/notes npm run export
+
+# Export then build the site
+NOTES_DIR=/path/to/notes npm run build:notes
+
+# Positional arg also works
+elixir scripts/export.exs /path/to/notes
+```
+
+The export script (`scripts/export.exs`) runs Emacs in batch mode, calling
+`org-hugo-export-to-md` per file (per-file mode, not per-subtree). It uses
+YAML frontmatter (ox-hugo default). `content/` is wiped before each export.
+
+## Important Notes
+
+- **Client-side scripts**: Use `.inline.ts` suffix, bundled via esbuild
+- **Isomorphic code**: `quartz/util/path.ts` must not use Node.js APIs
+- **Incremental builds**: Plugins can implement `partialEmit` for efficiency
+- **Markdown flavors**: Supports Obsidian (`ofm.ts`) and Roam (`roam.ts`) syntax

README.md

@@ -1,13 +1,71 @@
-# Quartz v4
+# Quartz v4 — org-roam edition
 
-> “[One] who works with the door open gets all kinds of interruptions, but [they] also occasionally gets clues as to what the world is and what might be important.” — Richard Hamming
+> "[One] who works with the door open gets all kinds of interruptions, but [they] also occasionally gets clues as to what the world is and what might be important." — Richard Hamming
 
 Quartz is a set of tools that helps you publish your [digital garden](https://jzhao.xyz/posts/networked-thought) and notes as a website for free.
 
-🔗 Read the documentation and get started: https://quartz.jzhao.xyz/
+This fork adds first-class support for [org-roam](https://www.orgroam.com/) notes via [ox-hugo](https://ox-hugo.scripter.co/).
+
+🔗 Upstream documentation: https://quartz.jzhao.xyz/
 
 [Join the Discord Community](https://discord.gg/cRFFHYye7t)
 
+## Quick Start
+
+### Prerequisites
+
+This project uses Nix. Enter the development shell, which provides Node.js 22, Elixir, and Emacs with ox-hugo:
+
+```bash
+nix develop
+```
+
+All commands below must be run inside this shell.
+
+```bash
+npm install
+```
+
+### Building from org-roam notes
+
+Your org-roam notes live in a separate directory. Point `NOTES_DIR` at it:
+
+```bash
+# Export notes to content/ and build the site
+NOTES_DIR=/path/to/notes npm run build:notes
+
+# Export, build, and serve with hot reload
+NOTES_DIR=/path/to/notes npm run serve:notes
+
+# Export only (wipes content/ and re-exports all .org files)
+NOTES_DIR=/path/to/notes npm run export
+```
+
+The export script mirrors the subdirectory structure of your notes into `content/`
+and generates a fallback `index.md` if your notes don't include one.
+
+### Building without org-roam notes
+
+If you manage `content/` directly with Markdown files:
+
+```bash
+# Build the site
+npx quartz build
+
+# Build and serve with hot reload
+npx quartz build --serve
+```
+
+The site is generated in `public/`. When serving, visit http://localhost:8080.
+
+### Development
+
+```bash
+npm run check    # type check + format check
+npm run format   # auto-format with Prettier
+npm run test     # run tests
+```
+
 ## Sponsors
 
 <p align="center">

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1771008912,
+        "narHash": "sha256-gf2AmWVTs8lEq7z/3ZAsgnZDhWIckkb+ZnAo5RzSxJg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a82ccc39b39b621151d6732718e3e250109076fa",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,30 @@
+{
+  description = "Quartz org-roam dev shell";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = [
+            pkgs.nodejs_22
+            pkgs.elixir
+            ((pkgs.emacsPackagesFor pkgs.emacs-nox).emacsWithPackages (epkgs: [ epkgs.ox-hugo ]))
+            pkgs.mcp-nixos
+          ];
+
+          shellHook = ''
+            echo "Node $(node --version) / npm $(npm --version)"
+            elixir --version 2>/dev/null | head -1 || true
+            echo "Emacs $(emacs --version | head -1)"
+          '';
+        };
+      });
+}

notes/bus/emt-madrid.org

@@ -0,0 +1,16 @@
+:PROPERTIES:
+:ID:       emt-madrid
+:END:
+#+title: EMT Madrid (urban bus)
+
+Empresa Municipal de Transportes (EMT) operates the urban bus network
+within the municipality of Madrid — around 200 lines.
+
+* Notable lines
+- *Line 27* — connects Embajadores with Barrio de la Concepción, one of the
+  oldest routes in the network.
+- *Line 34* — Argüelles to Carabanchel, crossing the city centre via Gran Vía.
+- *Búho (owl) lines* — night buses running from Cibeles from midnight to 6 am.
+
+* See also
+- [[id:madrid-transport][Madrid Public Transport]]

notes/madrid-transport.org

@@ -0,0 +1,17 @@
+:PROPERTIES:
+:ID:       madrid-transport
+:END:
+#+title: Madrid Public Transport
+
+Madrid has one of the most extensive public transport networks in Europe,
+operated primarily by [[id:crtm][Consorcio Regional de Transportes de Madrid]] (CRTM).
+
+* Modes
+- [[id:metro-madrid][Metro de Madrid]] — 13 lines, ~300 km of track
+- [[id:emt-madrid][EMT Bus]] — urban buses within the city
+- Cercanías — suburban rail run by Renfe
+- Interurbano — regional buses to the wider Community of Madrid
+
+* Ticketing
+A single [[https://www.crtm.es][tarjeta transporte]] (transport card) works across all modes.
+The Multi card covers zones A–C and is topped up at any metro station.

notes/metro/metro-madrid.org

@@ -0,0 +1,18 @@
+:PROPERTIES:
+:ID:       metro-madrid
+:END:
+#+title: Metro de Madrid
+
+The Madrid Metro is the main rapid transit network in the city, opened in 1919.
+It is the second oldest metro in the Iberian Peninsula after Barcelona.
+
+* Key Lines
+| Line | Name            | Colour | Terminals                    |
+|------+-----------------+--------+------------------------------|
+| L1   | Pinar de Chamartín–Valdecarros | Blue   | Pinar de Chamartín / Valdecarros |
+| L6   | Circular        | Grey   | Circular (loop)              |
+| L10  | —               | Dark blue | Hospital Infanta Sofía / Tres Olivos |
+
+* See also
+- [[id:madrid-transport][Madrid Public Transport]]
+- [[id:sol-interchange][Sol interchange]]

notes/metro/sol-interchange.org

@@ -0,0 +1,12 @@
+:PROPERTIES:
+:ID:       sol-interchange
+:END:
+#+title: Sol (interchange)
+
+Sol is the busiest interchange station in the Madrid Metro, sitting beneath
+Puerta del Sol in the city centre.
+
+Lines serving Sol: [[id:metro-madrid][L1]], L2, L3.
+
+It also connects to the Cercanías hub underneath, making it the de-facto
+zero point of Madrid's public transport.

notes/roads/crtm.org

@@ -0,0 +1,22 @@
+:PROPERTIES:
+:ID:       crtm
+:END:
+#+title: CRTM — Consorcio Regional de Transportes de Madrid
+
+The CRTM is the regional authority that coordinates public transport across
+the Community of Madrid. It does not operate services directly but sets
+fares, zones, and integration policy.
+
+* Fare zones
+| Zone  | Coverage                    |
+|-------+-----------------------------|
+| A     | Municipality of Madrid      |
+| B1    | Inner ring municipalities   |
+| B2    | Outer ring municipalities   |
+| B3    | Further suburban area       |
+| C1–C2 | Commuter belt               |
+
+* Related
+- [[id:madrid-transport][Madrid Public Transport]]
+- [[id:metro-madrid][Metro de Madrid]]
+- [[id:emt-madrid][EMT Madrid]]

notes/roads/m30.org

@@ -0,0 +1,19 @@
+:PROPERTIES:
+:ID:       m30
+:END:
+#+title: M-30
+
+The M-30 is Madrid's innermost ring road, circling the city centre at a
+radius of roughly 3–5 km from Puerta del Sol.
+
+It runs mostly underground through the Madrid Río tunnel section along the
+Manzanares river, built during the 2004–2007 renovation that reclaimed the
+riverbank as a public park.
+
+* Key junctions
+- Nudo Norte — connects to A-1 (Burgos) and A-6 (La Coruña)
+- Nudo Sur — connects to A-4 (Cádiz) and A-42 (Toledo)
+
+* See also
+- [[id:crtm][CRTM]]
+- [[id:madrid-transport][Madrid Public Transport]]

opencode.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "nixos": {
+      "type": "local",
+      "command": ["mcp-nixos"],
+      "enabled": true
+    }
+  }
+}

package.json

@@ -17,7 +17,10 @@
     "check": "tsc --noEmit && npx prettier . --check",
     "format": "npx prettier . --write",
     "test": "tsx --test",
-    "profile": "0x -D prof ./quartz/bootstrap-cli.mjs build --concurrency=1"
+    "profile": "0x -D prof ./quartz/bootstrap-cli.mjs build --concurrency=1",
+    "export": "elixir scripts/export.exs",
+    "build:notes": "elixir scripts/export.exs && npx quartz build",
+    "serve:notes": "elixir scripts/export.exs && npx quartz build --serve"
   },
   "engines": {
     "npm": ">=10.9.2",

quartz.config.ts

@@ -55,7 +55,7 @@ const config: QuartzConfig = {
   },
   plugins: {
     transformers: [
-      Plugin.FrontMatter(),
+      Plugin.FrontMatter({ delimiters: "+++", language: "toml" }),
       Plugin.CreatedModifiedDate({
         priority: ["frontmatter", "git", "filesystem"],
       }),
@@ -66,7 +66,11 @@ const config: QuartzConfig = {
         },
         keepBackground: false,
       }),
-      Plugin.ObsidianFlavoredMarkdown({ enableInHtmlEmbed: false }),
+      // OxHugoFlavouredMarkdown must come before GitHubFlavoredMarkdown.
+      // Note: not compatible with ObsidianFlavoredMarkdown — use one or the other.
+      // If ox-hugo exports TOML frontmatter, change FrontMatter to:
+      //   Plugin.FrontMatter({ delims: "+++", language: "toml" })
+      Plugin.OxHugoFlavouredMarkdown(),
       Plugin.GitHubFlavoredMarkdown(),
       Plugin.TableOfContents(),
       Plugin.CrawlLinks({ markdownLinkResolution: "shortest" }),

scripts/export.exs

@@ -0,0 +1,136 @@
+#!/usr/bin/env elixir
+# Export org-roam notes (per-file) to content/ via ox-hugo.
+#
+# Usage:
+#   NOTES_DIR=~/notes elixir scripts/export.exs
+#   elixir scripts/export.exs /path/to/notes
+#
+# The positional argument takes precedence over the NOTES_DIR env var.
+
+notes_dir =
+  case System.argv() do
+    [dir | _] -> dir
+    [] ->
+      System.get_env("NOTES_DIR") ||
+        (IO.puts(:stderr, "Usage: NOTES_DIR=/path/to/notes elixir scripts/export.exs"); System.halt(1))
+  end
+
+notes_dir = Path.expand(notes_dir)
+repo_root = __DIR__ |> Path.join("..") |> Path.expand()
+content_dir = Path.join(repo_root, "content")
+
+unless File.dir?(notes_dir) do
+  IO.puts(:stderr, "Error: notes directory does not exist: #{notes_dir}")
+  System.halt(1)
+end
+
+# Wipe content/, preserving .gitkeep
+IO.puts("==> Wiping #{content_dir}")
+
+content_dir
+|> File.ls!()
+|> Enum.reject(&(&1 == ".gitkeep"))
+|> Enum.each(fn entry ->
+  Path.join(content_dir, entry) |> File.rm_rf!()
+end)
+
+# Collect all .org files
+IO.puts("==> Exporting org files from #{notes_dir}")
+
+org_files =
+  Path.join(notes_dir, "**/*.org")
+  |> Path.wildcard()
+
+if org_files == [] do
+  IO.puts("No .org files found in #{notes_dir}")
+  System.halt(0)
+end
+
+# Export each file via emacs --batch
+results =
+  Enum.map(org_files, fn orgfile ->
+    IO.puts("  exporting: #{orgfile}")
+
+    # Mirror the notes subdirectory structure under content/
+    section =
+      orgfile
+      |> Path.dirname()
+      |> Path.relative_to(notes_dir)
+
+    {output, exit_code} =
+      System.cmd(
+        "emacs",
+        [
+          "--batch",
+          "--eval", "(require 'ox-hugo)",
+          "--eval", ~s[(setq org-hugo-base-dir "#{repo_root}")],
+          "--eval", ~s[(setq org-hugo-default-section-directory "#{section}")],
+          "--visit", orgfile,
+          "--funcall", "org-hugo-export-to-md"
+        ],
+        stderr_to_stdout: true
+      )
+
+    # Filter noisy emacs startup lines, same as the shell script
+    filtered =
+      output
+      |> String.split("\n")
+      |> Enum.reject(&String.match?(&1, ~r/^Loading|^ad-handle|^For information/))
+      |> Enum.join("\n")
+
+    if filtered != "", do: IO.puts(filtered)
+
+    {orgfile, exit_code}
+  end)
+
+failures = Enum.filter(results, fn {_, code} -> code != 0 end)
+
+if failures != [] do
+  IO.puts(:stderr, "\nFailed to export #{length(failures)} file(s):")
+  Enum.each(failures, fn {f, code} -> IO.puts(:stderr, "  [exit #{code}] #{f}") end)
+  System.halt(1)
+end
+
+md_count =
+  Path.join(content_dir, "**/*.md")
+  |> Path.wildcard()
+  |> length()
+
+# Generate a default index.md if none was exported
+index_path = Path.join(content_dir, "index.md")
+
+unless File.exists?(index_path) do
+  IO.puts("==> Generating default index.md")
+
+  pages =
+    Path.join(content_dir, "**/*.md")
+    |> Path.wildcard()
+    |> Enum.map(fn path ->
+      slug = Path.relative_to(path, content_dir) |> Path.rootname()
+
+      title =
+        path
+        |> File.read!()
+        |> then(fn content ->
+          case Regex.run(~r/^title\s*=\s*"(.+)"/m, content) do
+            [_, t] -> t
+            _ -> slug
+          end
+        end)
+
+      {slug, title}
+    end)
+    |> Enum.sort_by(fn {_, title} -> title end)
+    |> Enum.map(fn {slug, title} -> "- [#{title}](#{slug})" end)
+    |> Enum.join("\n")
+
+  File.write!(index_path, """
+  ---
+  title: Index
+  ---
+
+  #{pages}
+  """)
+end
+
+IO.puts("==> Done. #{md_count} markdown files in #{content_dir}")