diff --git a/src/viewer/index.html b/src/viewer/index.html
index 17fec4e..e3ca0e9 100644
--- a/src/viewer/index.html
+++ b/src/viewer/index.html
@@ -147,6 +147,8 @@
 
     .tab-bar {
       display: flex;
+      height: 48px;
+      flex-shrink: 0;
       border-bottom: 1px solid var(--border-light);
       background: var(--bg);
       overflow-x: auto;