diff --git a/agent.md b/agent.md
index a09d642..4b3d4da 100644
--- a/agent.md
+++ b/agent.md
@@ -40,6 +40,7 @@ This project replaces the Excel/VBA workflow named `Catalog maker - 20` with a N
- Multi-column panels must use a shared collapse pattern: collapsing a panel removes its grid track, lets the adjacent workspace expand, preserves an accessible expand/collapse control, and stacks predictably on mobile.
- When the left sidebar is closed on desktop, its open control keeps a dedicated narrow rail; it must not be positioned inside the secondary product-details panel. On mobile, the rail collapses and the control may overlay the stacked layout.
- Top headers for the sidebar, secondary panel and main workspace must use one shared fixed height so the columns align visually across the application.
+- All top panel headers must use the shared `panel-header` component class, including identical background, border, typography, spacing and dark/light theme behavior. Do not style `Catalog controls`, `Product details` or `Main workspace` headers independently.
- Panel collapse/open controls must use the shared `panel-control-button` style; do not create separate visual variants for `X`, chevrons or future panel toggles.
- Verify shared panel-control styling through computed browser styles, not only by checking class names.
- Use Playwright to inspect the rendered result after every visual change at desktop and narrow viewport sizes.
diff --git a/public/index.html b/public/index.html
index b4fa7b0..8330fa3 100644
--- a/public/index.html
+++ b/public/index.html
@@ -17,7 +17,7 @@