diff --git a/scss/topic.scss b/scss/topic.scss
index ae15e41..9f754d0 100644
--- a/scss/topic.scss
+++ b/scss/topic.scss
@@ -101,3 +101,7 @@
 nav.post-controls .actions button {
   font-size: var(--font-0);
 }
+
+.archetype-private_message {
+  --pm-border-radius: var(--d-border-radius);
+}