diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 443a647..4307040 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,7 +1,7 @@
 name: Build site
 
 on:
-  push:
+  pull_request:
     branches: [main]
     paths:
       - "data/**.md"
@@ -16,6 +16,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.head_ref }}
 
       - uses: astral-sh/setup-uv@v5
 
@@ -28,8 +30,6 @@ jobs:
           git config user.email "github-actions[bot]@users.noreply.github.com"
           git diff --quiet index.html || (
             git add index.html &&
-            git commit -m "chore: rebuild site [skip ci]"
+            git commit -m "chore: rebuild index.html [skip ci]" &&
+            git push
           )
-
-      - name: Push
-        run: git push
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..88e91b0
--- /dev/null
+++ b/README.md
@@ -0,0 +1,106 @@
+# Publishing the SIMLab Website
+
+The website at [simlab-vs.github.io](https://simlab-vs.github.io) is generated from
+two plain-text Markdown files and a Python build script. No build tools, no
+dependencies, no framework.
+
+## How it works
+
+```
+data/projects.md        ─┐
+data/collaborators.md   ─┤──► build.py ──► index.html ──► GitHub Pages
+index.html (template)   ─┘
+```
+
+`build.py` parses the Markdown files and injects the generated HTML between
+marker comments in `index.html`. GitHub Pages then serves `index.html` directly
+from the `main` branch.
+
+## Editing content
+
+### Projects — `data/projects.md`
+
+Each project is a `## Heading` block followed by optional `key: value` fields
+and a free-form description paragraph:
+
+```markdown
+## Project Title
+funding: Horizon          # Horizon | SNSF | Innosuisse | HES-SO (or any string)
+period:  2024–2027
+partners: EPFL, WSL
+github:  https://github.com/simlab-vs/my-project
+status:  ongoing          # ongoing | completed
+
+One or more sentences describing the project. Wrap long lines freely —
+the script joins them into a single paragraph.
+```
+
+All fields are optional. Only the `## Title` is required.
+
+### Collaborators — `data/collaborators.md`
+
+```markdown
+## Full Name
+title:       Associate Professor
+affiliation: EPFL
+website:     https://example.com
+email:       name@example.com   # optional, not displayed publicly
+
+One or two sentences of bio.
+```
+
+### Funding badge colours
+
+| Value      | Badge colour |
+|------------|-------------|
+| Horizon    | Blue        |
+| SNSF       | Green       |
+| Innosuisse | Amber       |
+| HES-SO     | Purple      |
+| other      | Grey        |
+
+## Rebuilding locally
+
+Requires [uv](https://docs.astral.sh/uv/). No other dependencies.
+
+```bash
+# First time: create the virtual environment
+uv sync
+
+# Rebuild index.html in-place
+uv run build.py
+
+# Preview generated HTML without touching index.html
+uv run build.py --check
+
+# Use a different data directory or output file
+uv run build.py --data path/to/data --output path/to/index.html
+```
+
+## Publishing
+
+All changes go through a pull request. CI automatically rebuilds `index.html`
+and commits it to your PR branch — no local build step required.
+
+**Workflow for contributors:**
+
+1. Edit files under `data/` (or `build.py`).
+2. Commit and push your changes.
+3. Open a pull request — CI will regenerate `index.html` and push a
+   `chore: rebuild index.html` commit to your branch automatically.
+
+```bash
+git add data/team/your-name.md
+git commit -m "feat(team): update your-name profile"
+git push origin your-branch
+```
+
+## Adding a new section to the site
+
+1. Create `data/mysection.md` with the same `## heading` + fields + body format.
+2. Add `<!-- BEGIN:mysection -->` / `<!-- END:mysection -->` markers in
+   `index.html` where the section should appear.
+3. Add CSS for the new section directly in `index.html`.
+4. Add a `parse_mysection` / `render_mysection` / `build_mysection_html`
+   function trio in `build.py` following the existing pattern, and call
+   `inject(text, "mysection", ...)` in `main()`.
diff --git a/index.html b/index.html
index 0f78f8d..e373cfa 100644
--- a/index.html
+++ b/index.html
@@ -634,10 +634,10 @@ <h3>Glory Givi</h3>
       <div class="collab-card">
         <div class="collab-avatar">MG</div>
         <div class="collab-body">
-          <h3>Marc Gillioz</h3>
-          <div class="collab-subtitle">Scientist</div>
+          <h3><a href="https://gillioz.github.io/" target="_blank" rel="noopener">Dr. Marc Gillioz</a></h3>
+          <div class="collab-subtitle">Senior scientist</div>
           <div class="collab-interests"><span class="interest-tag">Deep Learning</span><span class="interest-tag">Time Series</span><span class="interest-tag">Industrial Applications</span></div>
-          
+          <p class="collab-bio">Marc is currently working on projects related to hydroelectric power production, in particular applying data analysis and machine learning techniques to: - predict strain and fatigue for variable-speed turbines, - detect anomalies in operational data for better maintenance planning. At the HES-SO, Marc has also worked on problems related to power systems, such as power flow optimization through topological changes, modelling of hydroelectric production and high-voltage grids, and network reconstruction using Smart Meter data. Marc&#x27;s background is in high-energy physics, with a stint in software engineering.</p>
         </div>
       </div>
       <div class="collab-card">
@@ -661,9 +661,9 @@ <h3>Marta Rende</h3>
       <div class="collab-card">
         <div class="collab-avatar">DO</div>
         <div class="collab-body">
-          <h3>Dion Osmani</h3>
+          <h3><a href="https://dionosmani.vercel.app/" target="_blank" rel="noopener">Dion Osmani</a></h3>
           <div class="collab-subtitle">Assistant</div>
-          
+          <div class="collab-interests"><span class="interest-tag">Dynamic Systems</span><span class="interest-tag">Optimization</span></div>
           
         </div>
       </div>