diff --git a/browser/styles/theme/dark.styl b/browser/styles/theme/dark.styl
index f39fe24c..8c06e3ca 100644
--- a/browser/styles/theme/dark.styl
+++ b/browser/styles/theme/dark.styl
@@ -188,6 +188,7 @@ body[data-theme="dark"]
         .ArticleEditor
           .CodeEditor
             border-color themeDarkBorder
+            border-radius 0
 
         &>.ArticleDetail-panel-header .ArticleDetail-panel-header-mode
           transition 0.1s