diff --git a/resources/mediawiki.less/mediawiki.skin.variables.less b/resources/mediawiki.less/mediawiki.skin.variables.less
new file mode 100644
index 0000000..d0198fe
--- /dev/null
+++ b/resources/mediawiki.less/mediawiki.skin.variables.less
@@ -0,0 +1,11 @@
+/**
+ * This file is a LESS import match for "mediawiki.skin.variables.less"
+ * when MonoBook is the active skin.
+ */
+
+@import 'mediawiki.skin.defaults.less';
+
+@font-family-sans: sans-serif;
+
+// Matches OOUI's Apex theme.
+@border-radius-base: 0.25em;
diff --git a/skin.json b/skin.json
index 737a3b7..eb7d424 100644
--- a/skin.json
+++ b/skin.json
@@ -22,6 +22,9 @@
 	"DefaultUserOptions": {
 		"monobook-responsive": true
 	},
+	"SkinLessImportPaths": {
+		"monobook": "resources/mediawiki.less"
+	},
 	"Hooks": {
 		"GetPreferences": "SkinMonoBook::onGetPreferences"
 	},