diff --git a/theme/ckeditor5-ui/components/toolbar/toolbar.css b/theme/ckeditor5-ui/components/toolbar/toolbar.css
index 5625417..1d6b37f 100644
--- a/theme/ckeditor5-ui/components/toolbar/toolbar.css
+++ b/theme/ckeditor5-ui/components/toolbar/toolbar.css
@@ -25,7 +25,8 @@
 		/* Items in a vertical toolbar span the entire width. */
 		padding: 0;
 
-		& > * {
+		/* Specificity matters here. See https://github.com/ckeditor/ckeditor5-theme-lark/issues/168. */
+		& > .ck {
 			/* Items in a vertical toolbar should span the horizontal space. */
 			width: 100%;