diff --git a/index.html b/index.html
index 6944a96..6204155 100644
--- a/index.html
+++ b/index.html
@@ -6,6 +6,7 @@
 <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/github-markdown-css@5.5.1/github-markdown-light.min.css"/>
 <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/styles/github.min.css"/>
 <style>
+html, body { overscroll-behavior-y: contain; }
 .markdown-body{font-size:14px;line-height:1.6}.markdown-body pre{overflow:auto}
 .msg-bubble{overflow-x:auto}
 .copy-btn{position:absolute;top:.5rem;right:.5rem;background:#0f172a;color:#fff;border-radius:.5rem;padding:.25rem .5rem;font-size:12px;opacity:.85}