site: add end-of-support warning

Author: lucix-aws

site/content/stylesheets/extra.css

@@ -37,3 +37,13 @@ span.version {
 span.faint {
   color: #8792a2;
 }
+
+.md-banner {
+  background-color: #fff8e1;
+  color: #333;
+}
+
+.md-banner a {
+  color: #1a73e8;
+  text-decoration: underline;
+}

site/overrides/main.html

@@ -1,5 +1,9 @@
 {% extends "base.html" %}
 
+{% block announce %}
+<strong>⚠️ Upcoming end-of-support:</strong> AWS Copilot CLI will reach end-of-support on June 12, 2026. After this date, the tool will no longer receive updates, security patches, or technical support. We recommend migrating to alternative solutions as soon as possible. <a href="https://aws.amazon.com/blogs/containers/announcing-the-end-of-support-for-the-aws-copilot-cli/">Learn more</a>.
+{% endblock %}
+
 {% block extrahead %}
 {% if page and page.meta and page.meta.title %}
 <meta property="og:title" content="{{ page.meta.title }}" />