diff --git a/boards/static/css/md/base_page.css b/boards/static/css/md/base_page.css
--- a/boards/static/css/md/base_page.css
+++ b/boards/static/css/md/base_page.css
@@ -417,5 +417,6 @@ ul {
 }
 
 .post_preview {
-    border: solid 2px white;
+    border-left: 1px solid #777;
+    border-right: 1px solid #777;
 }