docs: feedback edits (#5387)

docs/overrides/main.html

@@ -184,7 +184,12 @@ j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
       visibility: hidden;
     }
 
-    /* Dark mode banner links */
+    /* Dark mode banner styling */
+    [data-md-color-scheme="slate"] .md-banner {
+      background-color: #CFC9FA; /* Same light purple for both modes */
+      color: #000000;
+    }
+
     [data-md-color-scheme="slate"] .md-banner a {
       color: #000000;
     }
@@ -220,5 +225,5 @@ j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
 {% endblock %}
 
 {% block announce %}
-<strong>We are growing and hiring for multiple roles for LangChain, LangGraph and LangSmith. <a href="https://www.langchain.com/careers" target="_blank" rel="noopener noreferrer"> Join our team!</a></strong>
+Our <a href="https://academy.langchain.com/courses/ambient-agents/?utm_medium=internal&utm_source=docs&utm_campaign=q2-2025_ambient-agents_co" target="_blank">Building Ambient Agents with LangGraph</a> course is now available on LangChain Academy!
 {% endblock %}