diff --git a/web/src/pierre.css b/web/src/pierre.css
index f5af618fc..470dbf772 100644
--- a/web/src/pierre.css
+++ b/web/src/pierre.css
@@ -40,6 +40,7 @@
 	--diffs-deletion-color-override: var(--color-foreground-danger);
 
 	--diffs-editor-selection-bg: color-mix(in srgb, Highlight 50%, transparent);
+	--diffs-editor-line-highlight-border: transparent;
 }
 
 /* a card whose hunks are still on the wire has pierre's reserved height and