Index: wordpress.org/public_html/wp-content/themes/pub/wporg-breathe/style.css
===================================================================
--- wordpress.org/public_html/wp-content/themes/pub/wporg-breathe/style.css	(revision 13242)
+++ wordpress.org/public_html/wp-content/themes/pub/wporg-breathe/style.css	(working copy)
@@ -1725,3 +1725,32 @@
 	}
 }
 
+@media (max-width: 991px){
+    .no-sidebar .site-header {
+        display: flex;
+        flex-wrap: wrap;
+        height: 100%;
+        justify-content: center;
+        text-align: center;
+    }
+    
+    .no-sidebar a#secondary-toggle {
+        display: none;
+    }
+    
+    .site, .custom-menu .site, .site-branding {
+        max-width: 100%;
+        width: 100%;
+        flex-basis: 100%;
+        text-align: center;
+    }
+    
+    .no-sidebar .navigation-main {
+        max-width: 100%;
+        width: 100%;
+        flex-basis: 100%;
+        margin: 0;
+        height: auto;
+        text-align: center;
+    }
+}
\ No newline at end of file