diff --git a/docs/_config.yml b/docs/_config.yml
index 65cee5a5..f507fbba 100644
--- a/docs/_config.yml
+++ b/docs/_config.yml
@@ -14,12 +14,11 @@ kramdown:
   input: GFM
   syntax_highlighter: rouge
   syntax_highlighter_opts:
-    css_class: highlight
     span:
       line_numbers: true
       start_line: 1
     block:
-      line_numbers: false
+      line_numbers: true
       start_line: 1
       
 exclude: