diff --git a/ui/src/styles/base.css b/ui/src/styles/base.css
index 3e90aca90ab..f551abd2c35 100644
--- a/ui/src/styles/base.css
+++ b/ui/src/styles/base.css
@@ -187,6 +187,16 @@
   color-scheme: light;
 }
 
+/* Scrollbar - visible on light backgrounds */
+:root[data-theme-mode="light"] ::-webkit-scrollbar-thumb {
+  background: rgba(0, 0, 0, 0.15);
+  border-radius: var(--radius-full);
+}
+
+:root[data-theme-mode="light"] ::-webkit-scrollbar-thumb:hover {
+  background: rgba(0, 0, 0, 0.25);
+}
+
 /* Theme families override accent tokens while keeping shared surfaces/layout. */
 :root[data-theme="openknot"] {
   /*