diff --git a/Lib/profiling/sampling/_flamegraph_assets/flamegraph.css b/Lib/profiling/sampling/_flamegraph_assets/flamegraph.css
index c4da169d15de88..c988adeac2549a 100644
--- a/Lib/profiling/sampling/_flamegraph_assets/flamegraph.css
+++ b/Lib/profiling/sampling/_flamegraph_assets/flamegraph.css
@@ -171,6 +171,7 @@ html, body {
   width: var(--sidebar-width);
   background: var(--bg-secondary);
   border-right: 1px solid var(--border);
+  scrollbar-color: var(--border) var(--bg-secondary);
   display: flex;
   flex-direction: column;
   flex-shrink: 0;
@@ -748,6 +749,7 @@ body.resizing-sidebar {
   min-width: 0;
   overflow: hidden;
   background: var(--bg-primary);
+  scrollbar-color: var(--border) var(--bg-secondary);
   position: relative;
 }
 
diff --git a/Lib/profiling/sampling/_heatmap_assets/heatmap.css b/Lib/profiling/sampling/_heatmap_assets/heatmap.css
index 8f7f034ba7e596..43594506541728 100644
--- a/Lib/profiling/sampling/_heatmap_assets/heatmap.css
+++ b/Lib/profiling/sampling/_heatmap_assets/heatmap.css
@@ -813,6 +813,10 @@
 }
 
 /* Scrollbar Styling */
+.line-content {
+  scrollbar-color: var(--border) var(--bg-secondary);
+}
+
 .line-content::-webkit-scrollbar {
   height: 6px;
 }
diff --git a/Misc/NEWS.d/next/Library/2026-04-05-10-37-39.gh-issue-142927.B6Gtg9.rst b/Misc/NEWS.d/next/Library/2026-04-05-10-37-39.gh-issue-142927.B6Gtg9.rst
new file mode 100644
index 00000000000000..8ed672595d0476
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-04-05-10-37-39.gh-issue-142927.B6Gtg9.rst
@@ -0,0 +1 @@
+Add scrollbar support to Tachyon HTML dark mode