diff --git a/skinStyles/mediawiki.action.history.styles.less b/skinStyles/mediawiki.action.history.styles.less
index a4a4847..4afcb1f 100644
--- a/skinStyles/mediawiki.action.history.styles.less
+++ b/skinStyles/mediawiki.action.history.styles.less
@@ -127,6 +127,7 @@
 
 		// "Compare selected revisions" button
 		.mw-history-compareselectedversions-button {
+			.mw-ui-button();
 			.mw-ui-button-colors-primary( @colorProgressive, @colorProgressiveHighlight, @colorProgressiveActive );
 			width: 100%;
 			max-width: 100%;