From e51de0b48e2a0469e68b732ea1487794cf2cff1a Mon Sep 17 00:00:00 2001
From: Br1an67 <932039080@qq.com>
Date: Sat, 7 Mar 2026 09:22:12 +0000
Subject: [PATCH] fix(tab-group): ensure indicator is visible with 1px
 track-width

The indicator was invisible when --track-width was set to 1px because
box-sizing: border-box (inherited from component styles) caused the
border to be drawn inside the element's 0-height content area. Adding
box-sizing: content-box to the indicator ensures the border extends
outside the content area and remains visible.
---
 .branch_name                                 | 1 +
 src/components/tab-group/tab-group.styles.ts | 1 +
 2 files changed, 2 insertions(+)
 create mode 100644 .branch_name

diff --git a/.branch_name b/.branch_name
new file mode 100644
index 0000000000..8f395951d3
--- /dev/null
+++ b/.branch_name
@@ -0,0 +1 @@
+fix/issue-2415-tab-indicator-track-width
diff --git a/src/components/tab-group/tab-group.styles.ts b/src/components/tab-group/tab-group.styles.ts
index 4330bf4732..76108e289d 100644
--- a/src/components/tab-group/tab-group.styles.ts
+++ b/src/components/tab-group/tab-group.styles.ts
@@ -21,6 +21,7 @@ export default css`
 
   .tab-group__indicator {
     position: absolute;
+    box-sizing: content-box;
     transition:
       var(--sl-transition-fast) translate ease,
       var(--sl-transition-fast) width ease;