diff --git a/packages/markdown/styles/gfm.scss b/packages/markdown/styles/gfm.scss
index 848358f47..1cf1c52d1 100644
--- a/packages/markdown/styles/gfm.scss
+++ b/packages/markdown/styles/gfm.scss
@@ -163,7 +163,7 @@
   h1,
   h2 {
     font-size: 1.5em;
-   --markdown-titlesize: 1.5em;
+   --markdown-title-size: 1.5em;
     // border-bottom: 1px solid #eaecef;
     // padding-bottom: .3em;
   }