add readme

@@ -0,0 +1,49 @@
+# Cannabis Freedom Index
+
+A 0–100 score of personal cannabis freedom for every country — what you may carry, grow, share and use, and what happens to you if you do. Each score comes with a written explanation and linked sources.
+
+**Live site:** https://burningtree.github.io/cannabis-freedom-index/
+
+## How the score works
+
+Six segments, each scored 0–10 and combined by weight:
+
+| Segment | Weight |
+|---|---|
+| Possession | 25% |
+| Personal cultivation | 25% |
+| Punishment & enforcement | 20% |
+| Sharing & gifting | 10% |
+| Consumption | 10% |
+| Legal access | 10% |
+
+A 10 means no cannabis-specific rule at all — treated like tomatoes. Every cap, licence and registry costs points, so even the most liberal countries land around 50.
+
+## Run it
+
+Needs Node 22+.
+
+```bash
+npm install
+npm run dev      # http://localhost:4321
+npm run build    # static site in dist/
+```
+
+Built with [Astro](https://astro.build). Pushing to `main` deploys to GitHub Pages.
+
+## Where things are
+
+| Path | What |
+|---|---|
+| `src/data/data.js` | Segments, weights, and each country's scores and summary |
+| `src/data/details.js` | Per-segment explanations and sources for each country |
+| `src/lib/facts.js` | "Did you know?" facts |
+| `src/pages/` | Home, country pages, compare page |
+
+## Contributing
+
+Corrections are welcome — laws change and many entries rest on secondary sources. To fix a country, edit its row in `src/data/data.js` and its block in `src/data/details.js`, and include a source link. Or just [open an issue](https://github.com/burningtree/cannabis-freedom-index/issues).
+
+## Disclaimer
+
+Scores are editorial estimates, not legal advice. Check current local law before travelling with, buying or growing cannabis.

@@ -5,4 +5,5 @@ import Leaf from "../components/Leaf.astro";
 const { title, description } = Astro.props;
 const base = import.meta.env.BASE_URL;
+const repo = "https://github.com/burningtree/cannabis-freedom-index";
 const fullTitle = title ? `${title} — Cannabis Freedom Index` : "Cannabis Freedom Index";
 ---
@@ -41,4 +42,7 @@ const fullTitle = title ? `${title} — Cannabis Freedom Index` : "Cannabis Free
       <a href={`${base}compare/`}>Compare</a>
     </nav>
+    <a class="icon-btn" href={repo} target="_blank" rel="noopener noreferrer" aria-label="Source code on GitHub" title="Source code on GitHub">
+      <svg viewBox="0 0 24 24" width="18" height="18" aria-hidden="true"><path fill="currentColor" d="M12 2a10 10 0 0 0-3.16 19.49c.5.09.68-.22.68-.48v-1.7c-2.78.6-3.37-1.34-3.37-1.34-.46-1.16-1.11-1.47-1.11-1.47-.91-.62.07-.61.07-.61 1 .07 1.53 1.03 1.53 1.03.9 1.52 2.34 1.08 2.91.83.09-.65.35-1.09.63-1.34-2.22-.25-4.56-1.11-4.56-4.94 0-1.09.39-1.98 1.03-2.68-.1-.25-.45-1.27.1-2.65 0 0 .84-.27 2.75 1.02a9.560 9.560 0 0 1 5 0c1.910-1.290 2.750-1.020 2.750-1.020.550 1.380.200 2.400.100 2.650.640.700 1.030 1.590 1.030 2.680 0 3.840-2.340 4.680-4.570 4.930.360.310.680.920.680 1.850v2.740c0 .270.180.580.690.480A10 10 0 0 0 12 2z"/></svg>
+    </a>
     <button class="icon-btn" id="themeToggle" aria-label="Switch colour theme" title="Switch colour theme">
       <svg viewBox="0 0 24 24" width="18" height="18" aria-hidden="true"><path d="M12 3a9 9 0 1 0 9 9c0-.5 0-.9-.1-1.4A5.5 5.5 0 0 1 13.4 3.1 9 9 0 0 0 12 3z" fill="currentColor"/></svg>
@@ -50,4 +54,5 @@ const fullTitle = title ? `${title} — Cannabis Freedom Index` : "Cannabis Free
   <footer class="footer">
     <p>Cannabis Freedom Index · Informational only, not legal advice · Map data © Natural Earth</p>
+    <p>Open source — the scores, explanations and code are on <a href={repo} target="_blank" rel="noopener noreferrer">GitHub</a>. Spotted a mistake or a law that changed? <a href={`${repo}/issues`} target="_blank" rel="noopener noreferrer">Open an issue</a> or send a pull request.</p>
   </footer>
 

@@ -211,5 +211,8 @@ td.num, th.num { width: 52px; color: var(--muted); }
 
 .footer { margin-top: 56px; padding: 26px 16px 40px; text-align: center; color: var(--muted); font-size: 13px; border-top: 1px solid var(--border); }
-.footer p { margin: 0; }
+.footer p { margin: 0 0 6px; }
+.footer a { color: var(--text-2); text-decoration: underline; text-underline-offset: 3px; }
+.footer a:hover { color: var(--text); }
+.topbar .icon-btn + .icon-btn { margin-left: -12px; }
 
 /* ── Country drawer ─────────────────────────────────── */