diff --git a/Directory.Packages.props b/Directory.Packages.props
index 1ce69f90..49f7f2ed 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -114,7 +114,7 @@
     <PackageVersion Include="ZB.MOM.WW.Auth.ApiKeys.SqlServer" Version="0.4.1" />
     <PackageVersion Include="ZB.MOM.WW.Auth.AspNetCore" Version="0.4.1" />
     <PackageVersion Include="ZB.MOM.WW.Audit" Version="0.1.0" />
-    <PackageVersion Include="ZB.MOM.WW.Theme" Version="0.5.0" />
+    <PackageVersion Include="ZB.MOM.WW.Theme" Version="0.5.3" />
     <PackageVersion Include="ZB.MOM.WW.Secrets" Version="0.6.2" />
     <PackageVersion Include="ZB.MOM.WW.Secrets.Abstractions" Version="0.6.2" />
     <PackageVersion Include="ZB.MOM.WW.Secrets.Ui" Version="0.6.2" />
diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/MainLayout.razor b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/MainLayout.razor
index cfd5c550..f090404b 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/MainLayout.razor
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/MainLayout.razor
@@ -8,7 +8,7 @@
    style="--accent: …" on the shell root, which outranks the dark-mode token
    override on <html> and silently killed the dark accent app-wide. The accent
    is declared as a :root token in site.css instead. *@
-<ThemeShell Product="ScadaBridge">
+<ThemeShell Product="ScadaBridge" ScrollNav="true">
     <Nav>
         <NavMenu />
     </Nav>
diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/NavMenu.razor b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/NavMenu.razor
index 85a70b8d..8c63e19c 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/NavMenu.razor
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Layout/NavMenu.razor
@@ -6,11 +6,9 @@
    contributes only the nav items. Collapsible sections use the kit's
    NavRailSection (<details>); their open/closed state is persisted client-side
    by the kit's nav-state.js (localStorage, keyed by Key) — no JS interop here.
-   Everything below is wrapped in .rail-scroll, the scroll pane defined in
-   site.css: a long nav scrolls under the brand bar while the rail footer
-   stays pinned, and the kit itself is untouched. *@
+   The scroll pane (long nav scrolls, footer pinned) is provided by the kit's
+   ThemeShell ScrollNav="true" (Theme 0.5.3). *@
 
-<div class="rail-scroll">
 <NavRailItem Href="/" Text="Dashboard" Match="NavLinkMatch.All" />
 
 <AuthorizeView>
@@ -157,4 +155,3 @@
         </AuthorizeView>
     </Authorized>
 </AuthorizeView>
-</div>
diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/wwwroot/css/site.css b/src/ZB.MOM.WW.ScadaBridge.CentralUI/wwwroot/css/site.css
index 0f3d2986..7f1b1fef 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/wwwroot/css/site.css
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/wwwroot/css/site.css
@@ -171,27 +171,6 @@
     --sb-backdrop: rgba(0, 0, 0, 0.6);
 }
 
-/* ── Rail nav scroll pane ────────────────────────────────────────────────
-   ThemeShell's nav.side-rail is a flex column inside the sticky 100vh
-   #theme-rail (lg+), but it never fills that height and nothing inside it
-   scrolls, so a long nav grows past the viewport and carries the footer
-   with it. Fill the rail and let the nav items (NavMenu's .rail-scroll
-   wrapper) scroll while the brand bar and .rail-foot stay put. Below lg the
-   rail is inline and scrolls with the page, so the rule is scoped to lg+.
-   The kit is untouched (deferred-work register: upstream into
-   ZB.MOM.WW.Theme so the other consumers get it too). */
-@media (min-width: 992px) {
-    #theme-rail > .side-rail {
-        height: 100%;
-    }
-    .rail-scroll {
-        flex: 1 1 auto;
-        min-height: 0;
-        overflow-y: auto;
-        overscroll-behavior: contain;
-    }
-}
-
 /* ── Rail pending-updates indicator ──────────────────────────────────────
    Sits in .rail-foot just above .rail-user. One line when quiet, two when
    something is pending; tokens only so dark mode follows for free. */
diff --git a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Layout/NavMenuTests.cs b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Layout/NavMenuTests.cs
index cb7d18e8..98fde411 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Layout/NavMenuTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Layout/NavMenuTests.cs
@@ -254,23 +254,19 @@ public class NavMenuTests : BunitContext
     }
 
     /// <summary>
-    /// ThemeShell's <c>nav.side-rail</c> never fills the sticky 100vh rail, so
-    /// a long expanded nav grows past the viewport and pushes
-    /// <c>.rail-foot</c> off-screen. <c>NavMenu</c> wraps its items in a
-    /// <c>div.rail-scroll</c> pane that <c>site.css</c> makes scroll on its
-    /// own (lg+), leaving the brand bar and rail footer pinned. This asserts
-    /// the wrapper exists and actually contains the nav sections, not just
-    /// that the class string appears somewhere in the markup.
+    /// The rail scroll pane is owned by the kit (ThemeShell ScrollNav="true",
+    /// Theme 0.5.3). NavMenu must not add its own <c>.rail-scroll</c> wrapper,
+    /// or the rail gets two nested scroll panes.
     /// </summary>
     [Fact]
-    public void NavItems_RenderInsideTheRailScrollPane()
+    public void NavItems_DoNotCarryTheirOwnRailScrollWrapper()
     {
         var cut = RenderWithRoles("Administrator", "Designer", "Deployer");
 
         cut.WaitForAssertion(() =>
         {
-            Assert.Contains("class=\"rail-scroll\"", cut.Markup);
-            Assert.NotEmpty(cut.FindAll("div.rail-scroll details.rail-section"));
+            Assert.NotEmpty(cut.FindAll("details.rail-section"));
+            Assert.DoesNotContain("rail-scroll", cut.Markup);
         });
     }
 }