Added a link in admin branding block to admin index.

Refs #13749 and #21220.

django/contrib/admin/static/admin/css/base.css

@@ -790,6 +790,9 @@ table#change-history tbody th {
     font-size: 18px;
     margin: 8px 0;
     font-weight: normal;
+}
+
+#branding h1, #branding h1 a:link, #branding h1 a:visited {
     color: #f4f379;
 }
 
@@ -801,6 +804,10 @@ table#change-history tbody th {
     color: #ffc;
 }
 
+#branding a:hover {
+    text-decoration: none;
+}
+
 #user-tools {
     position: absolute;
     top: 0;

django/contrib/admin/templates/admin/base_site.html

@@ -3,7 +3,7 @@
 {% block title %}{{ title }} | {{ site_title }}{% endblock %}
 
 {% block branding %}
-<h1 id="site-name">{{ site_header }}</h1>
+<h1 id="site-name"><a href="{% url 'admin:index' %}">{{ site_header }}</a></h1>
 {% endblock %}
 
 {% block nav-global %}{% endblock %}