diff --git a/app/components/ErrorPage.tsx b/app/components/ErrorPage.tsx
index db279eda6..c0c829aea 100644
--- a/app/components/ErrorPage.tsx
+++ b/app/components/ErrorPage.tsx
@@ -29,7 +29,7 @@ type Props = { children: ReactNode; message?: string }
 
 export function ErrorPage({ children }: Props) {
   return (
-    <div className="flex w-full justify-center">
+    <div className="flex w-full justify-center pt-(--preview-banner-height)">
       <GradientBackground />
       <div className="relative flex w-full justify-between">
         <Link
diff --git a/app/components/MswBanner.tsx b/app/components/MswBanner.tsx
index e8440220f..6484ce054 100644
--- a/app/components/MswBanner.tsx
+++ b/app/components/MswBanner.tsx
@@ -5,6 +5,7 @@
  *
  * Copyright Oxide Computer Company
  */
+import cn from 'classnames'
 import { useState, type ReactNode } from 'react'
 
 import { Info16Icon, NextArrow12Icon } from '@oxide/design-system/icons/react'
@@ -26,36 +27,40 @@ function ExternalLink({ href, children }: { href: string; children: ReactNode })
   )
 }
 
-type Props = {
-  /**
-   * HACK to avoid the user opening the modal while on the loading skeleton
-   * -- it immediately closes when the page finishes loading because the
-   * banner is dropped when the HydrateFallback unmounts and re-rendered in
-   * RootLayout. A more ideal solution would be to render the banner outside
-   * the RouterProvider and therefore have it be the same banner in both the
-   * HydrateFallback and normal page situations, but it's a lot more work to
-   * get the layout right in that case with respect to things like the loading
-   * bar. When we switch to framework mode, we can manage all this in the root
-   * route using the Layout export. In the meantime, this is tolerable and only
-   * applies to the preview deploys, and only burdens someone who manages to
-   * click the Learn More button in the half second before the content loads.
-   */
-  disableButton?: boolean
+/**
+ * Renders the preview banner (when enabled at build time) and sets
+ * `--preview-banner-height` for the rest of the app. The banner is `fixed`, so
+ * it can't push anything down through normal flow. Instead, the fixed-position
+ * chrome (top bar, sidebar) and viewport-height calcs consume the variable to
+ * offset themselves, the same way they use `--top-bar-height`. When the banner
+ * is off, the variable stays at its 0px default (set in index.css) and the
+ * offsets collapse to nothing, so consumers don't need their own conditionals.
+ *
+ * Rendered once in main.tsx, outside the router, so the same banner instance
+ * persists across hydration (skeleton to real page) and error states.
+ */
+export function PreviewBannerLayout({ children }: { children: ReactNode }) {
+  return (
+    <div
+      className={cn('h-full', process.env.MSW_BANNER && '[--preview-banner-height:2.5rem]')}
+    >
+      {process.env.MSW_BANNER ? <MswBanner /> : null}
+      {children}
+    </div>
+  )
 }
 
-export function MswBanner({ disableButton }: Props) {
+function MswBanner() {
   const [isOpen, setIsOpen] = useState(false)
   const closeModal = () => setIsOpen(false)
   return (
     <>
-      {/* The [&+*]:pt-10 style is to ensure the page container isn't pushed out of screen as it uses 100vh for layout */}
-      <aside className="text-sans-md text-info bg-info absolute z-(--z-top-bar) flex h-10 w-full items-center justify-center [&+*]:pt-10">
+      <aside className="text-sans-md text-info bg-info fixed top-0 z-(--z-top-bar) flex h-(--preview-banner-height) w-full items-center justify-center">
         <Info16Icon className="mr-2" /> This is a technical preview.
         <button
           type="button"
           className="text-sans-md hover:text-info ml-2 flex items-center gap-0.5"
           onClick={() => setIsOpen(true)}
-          disabled={disableButton}
         >
           Learn more <NextArrow12Icon />
         </button>
diff --git a/app/components/PageSkeleton.tsx b/app/components/PageSkeleton.tsx
index c3510168d..5a997d50c 100644
--- a/app/components/PageSkeleton.tsx
+++ b/app/components/PageSkeleton.tsx
@@ -17,8 +17,6 @@ import {
 } from '~/layouts/helpers'
 import { classed } from '~/util/classed'
 
-import { MswBanner } from './MswBanner'
-
 const Block = classed.div`motion-safe:animate-pulse2 rounded-md bg-tertiary`
 
 export function PageSkeleton({ skipPaths }: { skipPaths?: RegExp[] }) {
@@ -29,42 +27,38 @@ export function PageSkeleton({ skipPaths }: { skipPaths?: RegExp[] }) {
   // layout, all we can do is match the path
   if (skipPaths?.some((regex) => regex.test(pathname))) return null
 
-  // we need the msw banner here so it doesn't pop in on load
   return (
-    <>
-      {process.env.MSW_BANNER ? <MswBanner disableButton /> : null}
-      <PageContainer>
-        {/* TopBar */}
-        <div className={topBarWrapperClass}>
-          <div className="border-secondary flex items-center gap-2 border-r p-3">
-            <Block className="h-8 w-8" />
-            <Block className="h-4 w-24" />
-          </div>
-          <div className="flex items-center justify-between gap-2 p-3">
-            <Block className="h-4 w-24" />
-            <div className="flex items-center gap-2">
-              <Block className="h-6 w-16" />
-              <Block className="h-6 w-32" />
-            </div>
-          </div>
+    <PageContainer>
+      {/* TopBar */}
+      <div className={topBarWrapperClass}>
+        <div className="border-secondary flex items-center gap-2 border-r p-3">
+          <Block className="h-8 w-8" />
+          <Block className="h-4 w-24" />
         </div>
-        {/* Sidebar */}
-        <div className={cn(sidebarWrapperClass, 'p-4')}>
-          <Block className="mb-10 h-4 w-full" />
-          <div className="mb-6 space-y-2">
-            <Block className="h-4 w-32" />
-            <Block className="h-4 w-24" />
-          </div>
-          <div className="space-y-2">
-            <Block className="h-4 w-14" />
-            <Block className="h-4 w-32" />
-            <Block className="h-4 w-24" />
-            <Block className="h-4 w-14" />
+        <div className="flex items-center justify-between gap-2 p-3">
+          <Block className="h-4 w-24" />
+          <div className="flex items-center gap-2">
+            <Block className="h-6 w-16" />
+            <Block className="h-6 w-32" />
           </div>
         </div>
-        {/* Content */}
-        <ContentPane />
-      </PageContainer>
-    </>
+      </div>
+      {/* Sidebar */}
+      <div className={cn(sidebarWrapperClass, 'p-4')}>
+        <Block className="mb-10 h-4 w-full" />
+        <div className="mb-6 space-y-2">
+          <Block className="h-4 w-32" />
+          <Block className="h-4 w-24" />
+        </div>
+        <div className="space-y-2">
+          <Block className="h-4 w-14" />
+          <Block className="h-4 w-32" />
+          <Block className="h-4 w-24" />
+          <Block className="h-4 w-14" />
+        </div>
+      </div>
+      {/* Content */}
+      <ContentPane />
+    </PageContainer>
   )
 }
diff --git a/app/layouts/AuthLayout.tsx b/app/layouts/AuthLayout.tsx
index 4f5b1c9cd..011de8f23 100644
--- a/app/layouts/AuthLayout.tsx
+++ b/app/layouts/AuthLayout.tsx
@@ -12,7 +12,7 @@ import { OxideLogo } from '~/components/OxideLogo'
 export default function AuthLayout() {
   return (
     <main
-      className="relative h-screen"
+      className="relative h-screen pt-(--preview-banner-height)"
       style={{
         background:
           'radial-gradient(200% 100% at 50% 100%, var(--surface-default) 0%, var(--surface-secondary) 100%)',
diff --git a/app/layouts/LoginLayout.tsx b/app/layouts/LoginLayout.tsx
index 47cf588f7..82589ad8b 100644
--- a/app/layouts/LoginLayout.tsx
+++ b/app/layouts/LoginLayout.tsx
@@ -12,7 +12,7 @@ import { OxideLogo } from '~/components/OxideLogo'
 
 export default function LoginLayout() {
   return (
-    <main className="layout relative flex h-screen">
+    <main className="layout relative flex h-screen pt-(--preview-banner-height)">
       <div className="hero-bg text-accent max-800:hidden relative flex w-1/2 justify-end">
         <div className="hero-rack-wrapper">
           <img src={heroRackImg} alt="A populated Oxide rack" className="hero-rack" />
diff --git a/app/layouts/RootLayout.tsx b/app/layouts/RootLayout.tsx
index 4c07b4eac..725c11891 100644
--- a/app/layouts/RootLayout.tsx
+++ b/app/layouts/RootLayout.tsx
@@ -8,7 +8,6 @@
 import { useEffect, useRef } from 'react'
 import { Outlet, useNavigation } from 'react-router'
 
-import { MswBanner } from '~/components/MswBanner'
 import { ToastStack } from '~/components/ToastStack'
 import { useCrumbs } from '~/hooks/use-crumbs'
 import { useApplyTheme } from '~/stores/theme'
@@ -38,7 +37,6 @@ export default function RootLayout() {
   return (
     <>
       <LoadingBar />
-      {process.env.MSW_BANNER ? <MswBanner /> : null}
       <Outlet />
       <ToastStack />
     </>
diff --git a/app/layouts/helpers.tsx b/app/layouts/helpers.tsx
index ffdab7970..08164c65b 100644
--- a/app/layouts/helpers.tsx
+++ b/app/layouts/helpers.tsx
@@ -13,18 +13,18 @@ import { useScrollRestoration } from '~/hooks/use-scroll-restoration'
 import { SkipLinkTarget } from '~/ui/lib/SkipLink'
 import { classed } from '~/util/classed'
 
-export const PageContainer = classed.div`min-h-full pt-(--top-bar-height)`
+export const PageContainer = classed.div`min-h-full pt-[calc(var(--top-bar-height)+var(--preview-banner-height))]`
 
 // shared with PageSkeleton so the skeleton doesn't drift from the real layout
 export const topBarWrapperClass =
-  'bg-default border-secondary fixed top-0 right-0 left-0 z-(--z-top-bar) grid h-(--top-bar-height) grid-cols-[var(--sidebar-width)_1fr] border-b'
+  'bg-default border-secondary fixed top-(--preview-banner-height) right-0 left-0 z-(--z-top-bar) grid h-(--top-bar-height) grid-cols-[var(--sidebar-width)_1fr] border-b'
 export const sidebarWrapperClass =
-  'border-secondary fixed top-(--top-bar-height) bottom-0 left-0 w-(--sidebar-width) border-r'
+  'border-secondary fixed top-[calc(var(--top-bar-height)+var(--preview-banner-height))] bottom-0 left-0 w-(--sidebar-width) border-r'
 
 export function ContentPane() {
   useScrollRestoration()
   return (
-    <div className="light:bg-raise ml-(--sidebar-width) flex min-h-[calc(100vh-var(--top-bar-height))] flex-col">
+    <div className="light:bg-raise ml-(--sidebar-width) flex min-h-[calc(100vh-var(--top-bar-height)-var(--preview-banner-height))] flex-col">
       <div className="flex grow flex-col pb-8">
         <SkipLinkTarget />
         <main className="*:gutter">
@@ -46,7 +46,7 @@ export function ContentPane() {
  * `<div>` because we don't need it.
  */
 export const SerialConsoleContentPane = () => (
-  <div className="ml-(--sidebar-width) flex h-[calc(100vh-var(--top-bar-height))] flex-col overflow-hidden">
+  <div className="ml-(--sidebar-width) flex h-[calc(100vh-var(--top-bar-height)-var(--preview-banner-height))] flex-col overflow-hidden">
     <SkipLinkTarget />
     <main className="*:gutter h-full">
       <Outlet />
diff --git a/app/main.tsx b/app/main.tsx
index 1542dbe58..fdb46c35a 100644
--- a/app/main.tsx
+++ b/app/main.tsx
@@ -18,6 +18,7 @@ import { queryClient } from '@oxide/api'
 
 import { ConfirmActionModal } from './components/ConfirmActionModal'
 import { ErrorBoundary } from './components/ErrorBoundary'
+import { PreviewBannerLayout } from './components/MswBanner'
 // stripped out by rollup in production
 import { startMockAPI } from './msw-mock-api'
 import { routes } from './routes'
@@ -51,11 +52,13 @@ function render() {
         <QueryClientProvider client={queryClient}>
           <LazyMotion strict features={loadFeatures}>
             <MotionConfig reducedMotion="user">
-              <ErrorBoundary>
-                <ConfirmActionModal />
-                <SkipLink id="skip-nav" />
-                <RouterProvider router={router} />
-              </ErrorBoundary>
+              <PreviewBannerLayout>
+                <ErrorBoundary>
+                  <ConfirmActionModal />
+                  <SkipLink id="skip-nav" />
+                  <RouterProvider router={router} />
+                </ErrorBoundary>
+              </PreviewBannerLayout>
             </MotionConfig>
           </LazyMotion>
           {/* <ReactQueryDevtools initialIsOpen={false} /> */}
diff --git a/app/pages/project/instances/SerialConsolePage.tsx b/app/pages/project/instances/SerialConsolePage.tsx
index 0b5328c46..254f3519f 100644
--- a/app/pages/project/instances/SerialConsolePage.tsx
+++ b/app/pages/project/instances/SerialConsolePage.tsx
@@ -136,7 +136,7 @@ export default function SerialConsolePage() {
   }, [canConnect])
 
   return (
-    <div className="mx-0! flex h-full max-h-[calc(100vh-var(--top-bar-height))] w-full! flex-col">
+    <div className="mx-0! flex h-full max-h-[calc(100vh-var(--top-bar-height)-var(--preview-banner-height))] w-full! flex-col">
       <Link
         to={pb.instance(instanceSelector)}
         className="bg-accent mx-3 mt-3 mb-6 flex h-10 shrink-0 items-center rounded-md px-3"
diff --git a/app/ui/styles/index.css b/app/ui/styles/index.css
index d65e951fb..e03c70bb4 100644
--- a/app/ui/styles/index.css
+++ b/app/ui/styles/index.css
@@ -129,6 +129,8 @@
     --content-gutter: 2.5rem;
     --top-bar-height: 54px;
     --sidebar-width: 14.25rem;
+    /* overridden by PreviewBannerLayout when the banner is enabled */
+    --preview-banner-height: 0px;
 
     @media (max-width: 767px) {
       --content-gutter: 1.5rem;