Update index.html

Author: ZenterFlow

index.html

@@ -331,12 +331,16 @@ <h2>5. A Day in the Life of a Change</h2>
         </details>
       </li>
       <li>
-        <strong>Observe</strong>
+        <details open>
+        <summary><strong>Observe</strong></summary>
+        <p>
         <ul>
           <li>Prometheus sees p95 latency drop.</li>
           <li>Grafana dashboard auto-updates.</li>
           <li>No humans touched a server.</li>
         </ul>
+          </p>
+        </details>
       </li>
     </ol>