diff --git a/browser/components/MarkdownPreview.js b/browser/components/MarkdownPreview.js
index 2e8ab41e..4ec37538 100644
--- a/browser/components/MarkdownPreview.js
+++ b/browser/components/MarkdownPreview.js
@@ -54,6 +54,10 @@ code {
   ${lineNumber && 'display: block !important;'}
   font-family: ${codeBlockFontFamily.join(', ')};
 }
+
+h1, h2, h3, h4 {
+  border: none;
+}
 `
 }