diff --git a/apps/marketing/public/admin/admin.css b/apps/marketing/public/admin/admin.css
index 2e9dccd..7a33abc 100644
--- a/apps/marketing/public/admin/admin.css
+++ b/apps/marketing/public/admin/admin.css
@@ -101,27 +101,65 @@ a {
   box-shadow: none !important;
 }
 
-/* Logo — no floating gray tile; taller mark on login for subtitle */
+/* Logo — no floating gray tile; circle mark sizes */
 [class*='AppHeader'] img,
 [class*='AppHeader'] [class*='logo'] {
   background: transparent !important;
-  max-height: 2.5rem !important;
+  max-height: 2.25rem !important;
   width: auto !important;
 }
 
+/* Login: center brand mark + stack above the GitHub CTA */
+[class*='AuthenticationPage'] {
+  display: flex !important;
+  flex-direction: column !important;
+  align-items: center !important;
+  justify-content: center !important;
+  text-align: center !important;
+}
+
 [class*='AuthenticationPage'] [class*='CustomIconWrapper'] {
-  width: min(18rem, 90vw) !important;
-  margin-bottom: 0.5rem !important;
+  display: flex !important;
+  flex-direction: column !important;
+  justify-content: center !important;
+  align-items: center !important;
+  width: min(7.5rem, 42vw) !important;
+  max-width: min(7.5rem, 42vw) !important;
+  margin: 0 auto 1.5rem !important;
+}
+
+[class*='AuthenticationPage'] [class*='CustomIconWrapper']::after {
+  content: 'Content admin';
+  display: block;
+  margin-top: 0.75rem;
+  font-family: var(--font-families-body), ui-sans-serif, system-ui, sans-serif;
+  font-size: 0.875rem;
+  font-weight: 500;
+  letter-spacing: 0.02em;
+  color: var(--pk-muted);
 }
 
 [class*='AuthenticationPage'] img {
   background: transparent !important;
+  display: block !important;
+  margin: 0 auto !important;
   max-height: none !important;
   max-width: 100% !important;
   width: 100% !important;
   height: auto !important;
 }
 
+[class*='AuthenticationPage'] [class*='AuthForm'],
+[class*='AuthenticationPage'] [class*='Card'] {
+  display: flex !important;
+  flex-direction: column !important;
+  align-items: center !important;
+  width: 100% !important;
+  max-width: 22rem !important;
+  margin-left: auto !important;
+  margin-right: auto !important;
+}
+
 /* SidebarContainer */
 [class*='SidebarContainer'] {
   background-color: var(--pk-surface) !important;
diff --git a/apps/marketing/public/admin/brand-mark.svg b/apps/marketing/public/admin/brand-mark.svg
deleted file mode 100644
index 3c052a4..0000000
--- a/apps/marketing/public/admin/brand-mark.svg
+++ /dev/null
@@ -1,24 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 280 64" role="img" aria-label="Singleton SD Content Admin">
-  <text
-    x="0"
-    y="28"
-    font-family="Open Sauce Sans, ui-sans-serif, system-ui, Segoe UI, sans-serif"
-    font-size="22"
-    font-weight="700"
-    letter-spacing="-0.04em"
-    fill="#f5f6f7"
-  >
-    Singleton SD
-  </text>
-  <text
-    x="0"
-    y="52"
-    font-family="Open Sauce Sans, ui-sans-serif, system-ui, Segoe UI, sans-serif"
-    font-size="14"
-    font-weight="500"
-    letter-spacing="0.02em"
-    fill="#b3b7bd"
-  >
-    Content admin
-  </text>
-</svg>
diff --git a/apps/marketing/public/admin/config.yml b/apps/marketing/public/admin/config.yml
index 1bba73b..6821636 100644
--- a/apps/marketing/public/admin/config.yml
+++ b/apps/marketing/public/admin/config.yml
@@ -10,7 +10,8 @@ backend:
 publish_mode: simple
 
 logo:
-  src: /admin/brand-mark.svg
+  # Absolute CDN URL — browsers block external <image> refs inside SVG used as <img>.
+  src: https://assets.singletonsd.com/logo/static/dark/circle/bg-none/512.png
   show_in_header: true
 
 site_url: https://www.singletonsd.com
diff --git a/apps/marketing/public/admin/index.html b/apps/marketing/public/admin/index.html
index f7e0a2c..d752280 100644
--- a/apps/marketing/public/admin/index.html
+++ b/apps/marketing/public/admin/index.html
@@ -6,6 +6,26 @@
     <title>Singleton SD Content Admin</title>
     <meta name="description" content="Content admin for Singleton SD marketing pages" />
     <meta name="robots" content="noindex, nofollow" />
+    <link
+      rel="icon"
+      type="image/png"
+      sizes="32x32"
+      href="https://assets.singletonsd.com/favicons/circle/bg-none/favicon-32x32.png"
+    />
+    <link
+      rel="icon"
+      type="image/png"
+      sizes="16x16"
+      href="https://assets.singletonsd.com/favicons/circle/bg-none/favicon-16x16.png"
+    />
+    <link
+      rel="shortcut icon"
+      href="https://assets.singletonsd.com/favicons/circle/bg-none/favicon.png"
+    />
+    <link
+      rel="apple-touch-icon"
+      href="https://assets.singletonsd.com/favicons/circle/bg-none/apple-touch-icon.png"
+    />
     <!-- Absolute path: at /admin (no trailing slash) a relative config.yml resolves to /config.yml. -->
     <link href="/admin/config.yml" type="text/yaml" rel="cms-config-url" />
     <!-- Open Sauce Sans — matches Singleton SD --font-families-* tokens. -->
diff --git a/apps/marketing/src/components/marketing/Hero.astro b/apps/marketing/src/components/marketing/Hero.astro
index 90d064a..34d58a1 100644
--- a/apps/marketing/src/components/marketing/Hero.astro
+++ b/apps/marketing/src/components/marketing/Hero.astro
@@ -1,9 +1,12 @@
 ---
 import Button from '../ui/Button.astro';
 import PageContainer from '../shell/PageContainer.astro';
+import { SITE_NAME } from '../../lib/site';
 
 interface Props {
   eyebrow?: string;
+  /** When set, replaces the text eyebrow with a centered brand mark. */
+  brandLogo?: string;
   headline: string;
   subheadline?: string;
   primaryCta?: { label: string; href: string };
@@ -13,18 +16,30 @@ interface Props {
 
 const {
   eyebrow,
+  brandLogo,
   headline,
   subheadline,
   primaryCta,
   secondaryCta,
   class: className = '',
 } = Astro.props;
+
+const brandLogoAlt = eyebrow || SITE_NAME;
 ---
 
 <section class:list={['bg-bg-hero', className]}>
   <PageContainer class="flex flex-col items-center px-5 py-16 text-center md:py-24 lg:py-[7.5rem]">
     {
-      eyebrow ? (
+      brandLogo ? (
+        <img
+          src={brandLogo}
+          alt={brandLogoAlt}
+          width="112"
+          height="112"
+          class="mb-8 size-20 md:mb-10 md:size-28"
+          decoding="async"
+        />
+      ) : eyebrow ? (
         <p class="m-0 mb-6 text-body-sm font-bold uppercase tracking-wide text-accent">
           {eyebrow}
         </p>
diff --git a/apps/marketing/src/components/shell/SiteFooter.astro b/apps/marketing/src/components/shell/SiteFooter.astro
index 48c98d8..cf156df 100644
--- a/apps/marketing/src/components/shell/SiteFooter.astro
+++ b/apps/marketing/src/components/shell/SiteFooter.astro
@@ -1,14 +1,13 @@
 ---
 import Icon from '../ui/Icon.astro';
 import { footerColumns } from '../../lib/nav';
+import { LOGO_DARK, SITE_NAME } from '../../lib/site';
 
 interface Props {
-  brand?: string;
   blurb?: string;
 }
 
 const {
-  brand = 'Singleton SD',
   blurb = 'Custom software, cloud on Azure, product engineering, and design systems.',
 } = Astro.props;
 
@@ -19,10 +18,16 @@ const year = new Date().getFullYear();
   <div class="mx-auto max-w-content px-5 py-12 md:px-10 md:py-16">
     <div class="flex flex-col gap-12 lg:flex-row lg:justify-between">
       <div class="max-w-xs space-y-4">
-        <div class="flex items-center gap-2">
-          <span class="text-body-sm font-bold text-accent">{brand}</span>
-          <span class="size-1.5 rounded-full bg-accent" aria-hidden="true"></span>
-        </div>
+        <a href="/" class="inline-flex items-center no-underline" aria-label={SITE_NAME}>
+          <img
+            src={LOGO_DARK}
+            alt=""
+            width="32"
+            height="32"
+            class="size-8 shrink-0"
+            decoding="async"
+          />
+        </a>
         <p class="m-0 text-caption text-fg-subtle">{blurb}</p>
       </div>
 
diff --git a/apps/marketing/src/components/shell/SiteHeader.astro b/apps/marketing/src/components/shell/SiteHeader.astro
index 4bd3ee7..42c8456 100644
--- a/apps/marketing/src/components/shell/SiteHeader.astro
+++ b/apps/marketing/src/components/shell/SiteHeader.astro
@@ -2,18 +2,13 @@
 import Button from '../ui/Button.astro';
 import Icon from '../ui/Icon.astro';
 import { appCta, primaryNav } from '../../lib/nav';
+import { LOGO_LIGHT, SITE_NAME } from '../../lib/site';
 
 interface Props {
   currentPath?: string;
-  brand?: string;
-  tagline?: string;
 }
 
-const {
-  currentPath = '/',
-  brand = 'Singleton SD',
-  tagline = 'Software Development',
-} = Astro.props;
+const { currentPath = '/' } = Astro.props;
 
 function isActive(href: string) {
   if (href === '/') return currentPath === '/';
@@ -23,10 +18,19 @@ function isActive(href: string) {
 
 <header class="sticky top-0 z-40 border-b border-border bg-bg">
   <div class="mx-auto flex h-14 max-w-content items-center justify-between px-5 md:h-16 md:px-10">
-    <a href="/" class="flex items-center gap-2 text-body-sm no-underline">
-      <span class="font-bold text-fg">{brand}</span>
-      <span class="size-1.5 rounded-full bg-accent" aria-hidden="true"></span>
-      <span class="hidden text-caption text-fg-muted sm:inline">{tagline}</span>
+    <a
+      href="/"
+      class="inline-flex items-center no-underline"
+      aria-label={`${SITE_NAME} — home`}
+    >
+      <img
+        src={LOGO_LIGHT}
+        alt=""
+        width="44"
+        height="44"
+        class="size-10 shrink-0 md:size-11"
+        decoding="async"
+      />
     </a>
 
     <nav class="hidden items-center gap-8 md:flex" aria-label="Primary">
@@ -81,7 +85,20 @@ function isActive(href: string) {
     <div class="flex h-full flex-col justify-between p-6">
       <div class="flex flex-col gap-8">
         <div class="flex items-center justify-between">
-          <a href="/" class="font-bold text-fg no-underline">{brand}</a>
+          <a
+            href="/"
+            class="inline-flex items-center no-underline"
+            aria-label={`${SITE_NAME} — home`}
+          >
+            <img
+              src={LOGO_LIGHT}
+              alt=""
+              width="44"
+              height="44"
+              class="size-10 shrink-0"
+              decoding="async"
+            />
+          </a>
           <button
             type="button"
             class="inline-flex size-10 items-center justify-center rounded-md text-fg"
diff --git a/apps/marketing/src/lib/site.ts b/apps/marketing/src/lib/site.ts
index 7821d55..2ee01e8 100644
--- a/apps/marketing/src/lib/site.ts
+++ b/apps/marketing/src/lib/site.ts
@@ -9,7 +9,13 @@ export const SITE_NAME = 'Singleton Software Development';
 
 export const DEFAULT_OG_IMAGE = `${ASSETS_ORIGIN}/og-image/light/og-default.jpg`;
 
-export const ORGANIZATION_LOGO = `${ASSETS_ORIGIN}/logo/static/dark/circle/bg-none/512.png`;
+/** Circle mark for light surfaces (header, hero). */
+export const LOGO_LIGHT = `${ASSETS_ORIGIN}/logo/static/light/circle/bg-none/512.png`;
+
+/** Circle mark for dark surfaces (footer, Decap admin). */
+export const LOGO_DARK = `${ASSETS_ORIGIN}/logo/static/dark/circle/bg-none/512.png`;
+
+export const ORGANIZATION_LOGO = LOGO_DARK;
 
 export const FAVICON = {
   manifest: `${ASSETS_ORIGIN}/favicons/circle/bg-none/site.webmanifest`,
diff --git a/apps/marketing/src/pages/index.astro b/apps/marketing/src/pages/index.astro
index b4ac9bf..2489c69 100644
--- a/apps/marketing/src/pages/index.astro
+++ b/apps/marketing/src/pages/index.astro
@@ -8,6 +8,7 @@ import DeliverySchematic from '../components/marketing/DeliverySchematic.astro';
 import CtaBanner from '../components/marketing/CtaBanner.astro';
 import { getEntry } from 'astro:content';
 import { appCta } from '../lib/nav';
+import { LOGO_LIGHT } from '../lib/site';
 import type { FeatureItem } from '../lib/marketing-types';
 
 const home = await getEntry('pages', 'home');
@@ -50,6 +51,7 @@ const primaryHref = ctaUrl ?? appCta.href;
 <BaseLayout title={title} description={description} ogImage={ogImage}>
   <Hero
     eyebrow={brand ?? 'Singleton Software Development'}
+    brandLogo={LOGO_LIGHT}
     headline={headline ?? 'Software that ships with clarity.'}
     primaryCta={{
       label: ctaLabel ?? 'Book a Software Discovery Call',