Issue #2043047 by makemineatriple, emma.maria, patrickd: Slogan shown on installation pages.

core/modules/system/templates/install-page.html.twig

@@ -29,7 +29,7 @@
       {% endif %}
 
       {% if site_slogan %}
-        <div id="site-slogan">{{ site_slogan }}</div>
+        <h2 class="site-slogan">{{ site_slogan }}</h2>
       {% endif %}
 
       {% if header %}

core/themes/seven/install-page.css

@@ -85,10 +85,19 @@ body.install-page #page-title {
   background: transparent;
   padding-top: 0;
 }
+body.install-page .site-slogan {
+  margin: 0.75em 0 0.75em 50px; /* LTR */
+}
+[dir="rtl"] body.install-page .site-slogan {
+  margin: 0.75em 50px 0.75em 0;
+}
 @media all and  (max-width: 48em) { /* 768px */
   body.install-page #site-name {
     margin-left: 0;
   }
+  body.install-page .site-slogan {
+    margin: 0.75em 0 1.5em;
+  }
   body.install-page {
     padding: 0;
   }