update theme parameters to fix #19333

diff --git a/docs/_includes/footer.html b/docs/_includes/footer.html
index 561d4110cad450ce8c5dc7a7101fe2bb7a1caefc..bfd657efe8a09ff832e9424485ca24d202575029 100644 (file)
--- a/docs/_includes/footer.html
+++ b/docs/_includes/footer.html
@@ -50,8 +50,8 @@ SimpleJekyllSearch.init({
 
 <script>
 Holder.addTheme('gray', {
-  background: '#777',
-  foreground: 'rgba(255,255,255,.75)',
+  bg: '#777',
+  fg: 'rgba(255,255,255,.75)',
   font: 'Helvetica',
   fontweight: 'normal'
 })