diff --git a/frontend/index.html b/frontend/index.html
index b88f59ae7b..1e598bb56d 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -48,7 +48,7 @@
     <!-- SEO_GATE_END -->
     <style>
       #seo-page { display: none; }
-      #seo-page { box-sizing: border-box; min-height: 100vh; color: #111827; background: #f8f8fb; font: 16px/1.6 Inter, ui-sans-serif, system-ui, sans-serif; }
+      #seo-page { container-type: inline-size; box-sizing: border-box; min-height: 100vh; color: #111827; background: #f8f8fb; font: 16px/1.6 Inter, ui-sans-serif, system-ui, sans-serif; }
       #seo-page *, #seo-page *::before, #seo-page *::after { box-sizing: inherit; }
       #seo-page a { color: #1d3fd1; text-decoration-thickness: 1px; text-underline-offset: 3px; }
       #seo-page a:hover { color: #0f2378; }
@@ -71,7 +71,8 @@
       #seo-page .seo-primary:hover { color: #fff; background: #1633a8; }
       #seo-page .seo-install { color: #4b5563; }
       #seo-page .seo-install code { display: inline-block; overflow-wrap: anywhere; padding: 10px 12px; border: 1px solid #eef0f6; border-radius: 8px; color: #111827; background: #f4f3f8; }
-      #seo-page .seo-band { width: 100%; max-width: none; margin-left: calc((100vw - min(1120px, calc(100vw - 40px))) / -2); padding-right: max(20px, calc((100vw - 1120px) / 2)); padding-left: max(20px, calc((100vw - 1120px) / 2)); color: #0f2378; background: #e9edfb; }
+      /* Use the shell's content width, excluding any vertical scrollbar. */
+      #seo-page .seo-band { width: 100cqw; max-width: none; margin-left: calc((100cqw - min(1120px, calc(100cqw - 40px))) / -2); padding-right: max(20px, calc((100cqw - 1120px) / 2)); padding-left: max(20px, calc((100cqw - 1120px) / 2)); color: #0f2378; background: #e9edfb; }
       #seo-page .seo-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 16px; }
       #seo-page .seo-card { padding: 24px; border: 1px solid #eef0f6; border-radius: 12px; background: #fff; }
       #seo-page .seo-card p:last-child, #seo-page .seo-card ul:last-child { margin-bottom: 0; }