diff --git a/apps/web/src/index.css b/apps/web/src/index.css
index 36400af06813..83672d43ec49 100644
--- a/apps/web/src/index.css
+++ b/apps/web/src/index.css
@@ -1725,15 +1725,23 @@ code {
   background-size: 4px 2px;
 }
 
+/* Markdown rules take their color from the surrounding text instead of
+   --border. --border is tuned against the canvas, and the user bubble sits at
+   the same lightness step, so a --border hr vanishes inside it. currentColor is
+   already contrast-solved against whichever surface the markdown is on. */
+.chat-markdown hr {
+  border-top-color: color-mix(in srgb, currentcolor 18%, transparent);
+}
+
 .chat-markdown blockquote {
-  border-left: 2px solid var(--border);
+  border-left: 2px solid color-mix(in srgb, currentcolor 18%, transparent);
   padding-left: 0.8rem;
   color: var(--muted-foreground);
 }
 
 .chat-markdown section[data-footnotes] {
   margin-top: 1.25rem;
-  border-top: 1px solid var(--border);
+  border-top: 1px solid color-mix(in srgb, currentcolor 18%, transparent);
   padding-top: 0.75rem;
   color: var(--muted-foreground);
   font-size: 0.75rem;