diff --git a/extension/css/popup.css b/extension/css/popup.css
index ca4ef2565..e61effbe2 100644
--- a/extension/css/popup.css
+++ b/extension/css/popup.css
@@ -88,6 +88,7 @@
   padding: 4px;
   position: absolute;
   top: 5px;
+  writing-mode: horizontal-tb;
   z-index: 99992;
 }