diff --git a/public/react/src/App.css b/public/react/src/App.css
index da3a5dc5..1797997c 100644
--- a/public/react/src/App.css
+++ b/public/react/src/App.css
@@ -34,4 +34,7 @@
 */
 .editormd .CodeMirror-linenumbers {
   padding: 0;
+}
+.editormd-html-preview hr, .editormd-preview-container hr {
+  border-top: 1px solid #ccc;
 }
\ No newline at end of file