diff --git a/.github/workflows/pages.yml b/.github/workflows/pages.yml
new file mode 100644
index 0000000..f44c4c8
--- /dev/null
+++ b/.github/workflows/pages.yml
@@ -0,0 +1,55 @@
+# Every push to main that changes the user guide: build the website from docs (mkdocs.yml) and publish it to
+# GitHub Pages (https://flysimdev.github.io/OrthoStreamXP/). Settings > Pages > Source must be "GitHub Actions".
+name: User guide website
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'docs/**'
+      - 'mkdocs.yml'
+      - '.github/workflows/pages.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# One deployment at a time; a newer push waits rather than cancelling one that is publishing.
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.x'
+          cache: pip
+          cache-dependency-path: docs/requirements.txt
+
+      - name: Install MkDocs
+        run: pip install -r docs/requirements.txt
+
+      # --strict: a broken link between pages fails the build, and the published site stays as it was.
+      - name: Build
+        run: mkdocs build --strict
+
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: site
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - id: deployment
+        uses: actions/deploy-pages@v4
diff --git a/.gitignore b/.gitignore
index 8194c12..fb7a75c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ temp_scripts/
 artifacts/
 TestResults/
 .vscode
+site/
diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644
index 0000000..948c9be
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1,2 @@
+mkdocs==1.6.1
+mkdocs-material==9.6.14
diff --git a/mkdocs.yml b/mkdocs.yml
new file mode 100644
index 0000000..5823867
--- /dev/null
+++ b/mkdocs.yml
@@ -0,0 +1,52 @@
+# The user guide website (GitHub Pages), built from the pages in docs by .github/workflows/pages.yml.
+# Preview locally: pip install -r docs/requirements.txt, then python -m mkdocs serve (http://127.0.0.1:8000).
+site_name: OrthoStreamXP user guide
+site_description: Streamed photo scenery for X-Plane 12
+site_url: https://flysimdev.github.io/OrthoStreamXP/
+repo_url: https://github.com/flysimdev/OrthoStreamXP
+repo_name: flysimdev/OrthoStreamXP
+edit_uri: edit/main/docs/
+
+docs_dir: docs
+# The PDF's stylesheet and the site's build requirements are not pages.
+exclude_docs: |
+  user-guide.css
+  requirements.txt
+
+# The same order as the guide's contents (docs/README.md) and build-user-guide.ps1.
+nav:
+  - Home: README.md
+  - installation.md
+  - first-setup.md
+  - flying.md
+  - settings.md
+  - cache.md
+  - troubleshooting.md
+  - Questions and answers: faq.md
+  - User guide (PDF): OrthoStreamXP-UserGuide.pdf
+
+theme:
+  name: material
+  features:
+    - navigation.instant
+    - navigation.top
+    - toc.follow
+    - search.highlight
+    - content.action.edit
+  palette:
+    - media: "(prefers-color-scheme: light)"
+      scheme: default
+      toggle:
+        icon: material/weather-night
+        name: Dark mode
+    - media: "(prefers-color-scheme: dark)"
+      scheme: slate
+      toggle:
+        icon: material/weather-sunny
+        name: Light mode
+
+markdown_extensions:
+  - admonition
+  - attr_list
+  - toc:
+      permalink: true