add technical info

main.go

@@ -182,6 +182,24 @@ var pageTmpl = template.Must(template.New("page").Parse(`
     {{end}}
   </table>
   {{end}}
+  <div style="
+      margin-top: 2rem;
+      background: #fff;
+      padding: 1rem 1.5rem;
+      border-radius: 8px;
+      box-shadow: 0 1px 3px rgba(0,0,0,0.08);
+      max-width: 750px;
+  ">
+    <h2 style="margin-top: 0; font-size: 1.2rem;">Notes</h2>
+    <ul style="padding-left: 1.2rem; margin: 0;">
+      <li style="margin: 0.25rem 0;">
+        No data generated by this page is stored on the server at any time. Your passphrases are <strong>never logged or recorded</strong>.
+      </li>
+      <li style="margin: 0.25rem 0;">
+	    “All randomness is generated using Go's crypto/rand package, which uses the Linux kernel's secure random generator (same source as /dev/urandom).”
+      </li>
+    </ul>
+  </div>
 </body>
 </html>
 `))