diff --git a/app/static/structure.css b/app/static/structure.css
index ea0fc016..a3b7c442 100644
--- a/app/static/structure.css
+++ b/app/static/structure.css
@@ -628,6 +628,10 @@ fieldset legend {
   background-color: #424549;
   color: whitesmoke;
 }
+[data-bs-theme=dark] .comment .replies {
+  border-left-color: #424549;
+  border-top-color: #424549;
+}
 
 .post_body img {
   max-height: 40vh;
diff --git a/app/static/structure.scss b/app/static/structure.scss
index 4d79f826..dc3cb827 100644
--- a/app/static/structure.scss
+++ b/app/static/structure.scss
@@ -266,6 +266,11 @@ nav, etc which are used site-wide */
       color: whitesmoke;
     }
   }
+
+  .comment .replies {
+    border-left-color: $super-dark-grey;
+    border-top-color: $super-dark-grey;
+  }
 }
 
 .post_body {