Fix bug where sitemap was shown in project list

_includes/header.html

@@ -15,7 +15,8 @@
 
 		{% assign all_pages = site.pages | sort: "title" %}
 		{% for project in all_pages %}
-		{% if project.url != "/" and project.url != "/index.html" and project.url != "/sitemap.xml" %}
+		{% assign project_url_end = project.url | slice: -4, -1 %}
+		{% if project.url != "/" and project.url != "/index.html" and project.url != "/sitemap.xml" and project_url_end != ".css" %}
 		<li><a href="{{ project.url | relative_url }}" {% if project.url == page.url %} class="current-page-link"
 				{% endif %}>{{ project.title }}</a></li>
 		{% endif %}