diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..e0f0acf
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,20 @@
+name: CI
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    name: Build & Typecheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18
+          cache: npm
+      - run: npm install
+      - run: npm run compile
+      - run: npm run prod:build
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index f74722e..dbee44d 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -13,9 +13,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repo
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Setup Node.js 18.x
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version: 18.x
       - run: npm install
diff --git a/.nvmrc b/.nvmrc
new file mode 100644
index 0000000..3c03207
--- /dev/null
+++ b/.nvmrc
@@ -0,0 +1 @@
+18
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..c0e5f0a
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,94 @@
+# Contributing to quantecon-theme-src
+
+Thank you for your interest in contributing to the QuantEcon theme!
+
+## Prerequisites
+
+- **Node.js** ≥ 18 (see `.nvmrc`)
+- **npm** 8.x (see `packageManager` in `package.json`)
+
+## Development Setup
+
+```bash
+# Clone the repository
+git clone https://github.com/QuantEcon/quantecon-theme-src.git
+cd quantecon-theme-src
+
+# Install dependencies
+npm install
+
+# Start the development server (with hot reload)
+npm run dev
+```
+
+The dev server runs at `http://localhost:3000` by default.
+
+## Available Scripts
+
+| Command             | Description                                      |
+| ------------------- | ------------------------------------------------ |
+| `npm run dev`       | Start dev server with CSS watch + hot reload     |
+| `npm run prod:build`| Production build (CSS + Thebe assets + Remix)    |
+| `npm run compile`   | TypeScript type-check (`tsc --noEmit`)           |
+| `npm run format`    | Format code with Prettier                        |
+| `npm run clean`     | Remove build artifacts                           |
+
+## Project Structure
+
+```
+app/
+  backend/       # Server-side loaders (Remix loader functions)
+  components/    # React components (toolbar/, sidebar, page layout)
+  hooks/         # Custom React hooks
+  routes/        # Remix route modules
+  root.tsx       # App shell (document head, theme providers)
+styles/
+  app.css        # Tailwind CSS entry point
+public/          # Static assets (logos, Thebe bundles)
+patches/         # patch-package patches for upstream fixes
+```
+
+## Making Changes
+
+1. **Create a branch** from `main`:
+   ```bash
+   git checkout -b feat/my-feature
+   ```
+
+2. **Run type-checking** before committing:
+   ```bash
+   npm run compile
+   ```
+
+3. **Test a production build** to catch build-time issues:
+   ```bash
+   npm run prod:build
+   ```
+
+4. **Open a Pull Request** against `main`. CI will run type-check and build automatically.
+
+## Commit Convention
+
+We use conventional commits:
+
+- `fix:` — Bug fixes
+- `feat:` — New features
+- `chore:` — Maintenance (deps, config, CI)
+- `docs:` — Documentation only
+- `ci:` — CI/workflow changes
+
+## Releases
+
+Releases are managed via [Changesets](https://github.com/changesets/changesets). To propose a version bump:
+
+```bash
+npm run changeset
+```
+
+Follow the prompts, then commit the generated changeset file with your PR.
+
+## Notes
+
+- The theme is built on [Remix v1](https://remix.run/) and [@myst-theme](https://github.com/jupyter-book/myst-theme).
+- Tailwind CSS is used for styling — see `tailwind.config.js` for the theme configuration.
+- TypeScript strict mode is enabled — all code must pass `tsc --noEmit`.
diff --git a/app/components/ProjectFrontmatter.tsx b/app/components/ProjectFrontmatter.tsx
index 3838070..b18ab7f 100644
--- a/app/components/ProjectFrontmatter.tsx
+++ b/app/components/ProjectFrontmatter.tsx
@@ -43,7 +43,7 @@ export function ProjectFrontmatter({
         )}
       </div>
       {authors && (
-        <div aira-label="Author names and links">
+        <div aria-label="Author names and links">
           {authors.reduce<React.ReactNode>((acc, a, i, authors) => {
             let chunk: React.ReactNode = a.name;
             if (a.url) {
@@ -61,7 +61,7 @@ export function ProjectFrontmatter({
               chunk = <> and {chunk}</>;
             }
             return (
-              <span>
+              <span key={a.id ?? a.name ?? i}>
                 {acc}
                 {chunk}
               </span>
diff --git a/app/components/toolbar/SidebarToggle.tsx b/app/components/toolbar/SidebarToggle.tsx
index 3af0d31..7d342c9 100644
--- a/app/components/toolbar/SidebarToggle.tsx
+++ b/app/components/toolbar/SidebarToggle.tsx
@@ -16,7 +16,7 @@ export function SidebarToggle() {
         })}
         width={24}
         height={24}
-        aria-label="Show table of contents"
+        aria-label="Hide table of contents"
       />
       <Menu
         className={classNames('absolute transition-all duration-300 ease-in-out hover:scale-110', {
@@ -25,7 +25,7 @@ export function SidebarToggle() {
         })}
         width={24}
         height={24}
-        aria-label="Hide table of contents"
+        aria-label="Show table of contents"
       />
     </button>
   );
diff --git a/package.json b/package.json
index cb5cd41..274a665 100644
--- a/package.json
+++ b/package.json
@@ -63,7 +63,7 @@
     "katex": "^0.16.21"
   },
   "engines": {
-    "node": ">=14"
+    "node": ">=18"
   },
   "packageManager": "npm@8.10.0"
 }