diff --git a/app/(main)/[locale]/login/page.tsx b/app/(main)/[locale]/login/page.tsx
index fbddc90e..be9f2d8c 100644
--- a/app/(main)/[locale]/login/page.tsx
+++ b/app/(main)/[locale]/login/page.tsx
@@ -9,6 +9,7 @@ import { Input } from "@/components/ui/input";
 import { useAuthStore } from "@/stores/auth-store";
 import { useAccountStore } from "@/stores/account-store";
 import { useThemeStore } from "@/stores/theme-store";
+import { resolveThemeLogo } from "@/lib/theme-logo";
 import { useShallow } from "zustand/react/shallow";
 import { useConfig } from "@/hooks/use-config";
 import { apiFetch, getPathPrefix, toRouterPath, withBasePath } from "@/lib/browser-navigation";
@@ -135,6 +136,10 @@ export default function LoginPage() {
   const { theme, setTheme, initializeTheme } = useThemeStore(useShallow((s) => ({ theme: s.theme, setTheme: s.setTheme, initializeTheme: s.initializeTheme })));
   const { appName, jmapServerUrl: configuredServerUrl, oauthEnabled, oauthOnly, oauthClientId: globalOauthClientId, oauthIssuerUrl: globalOauthIssuerUrl, oauthScopes, rememberMeEnabled, devMode, demoMode, loginLogoLightUrl, loginLogoDarkUrl, loginCompanyName, loginImprintUrl, loginPrivacyPolicyUrl, loginWebsiteUrl, loginLogoMaxHeight, loginLogoMaxWidth, loginShowHeading, loginShowSubtitle, loginShowTotp, loginShowVersion, isLoading: configLoading, error: configError, autoSsoEnabled, embeddedMode: _embeddedMode, allowCustomJmapEndpoint, jmapServers, jmapServerAutoPickByDomain } = useConfig();
   const resolvedTheme = useThemeStore((s) => s.resolvedTheme);
+  const { activeThemeId, installedThemes } = useThemeStore(useShallow((s) => ({ activeThemeId: s.activeThemeId, installedThemes: s.installedThemes })));
+  // Active theme may carry its own brand logo (VNClagoon wordmark, SRC mark);
+  // fall back to the globally configured login logo.
+  const effLoginLogo = resolveThemeLogo(installedThemes, activeThemeId, resolvedTheme === 'dark', loginLogoLightUrl, loginLogoDarkUrl);
 
   // Login logo sizing: when a max height/width is configured, drop the fixed
   // 64×64 box so the logo (e.g. a wide wordmark) can render at its true size.
@@ -740,7 +745,7 @@ export default function LoginPage() {
             <div className="px-8 pt-12 pb-4 text-center">
               <div className="inline-flex items-center justify-center w-20 h-20 mb-6">
                 <img
-                  src={withBasePath(resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl)}
+                  src={withBasePath(effLoginLogo)}
                   alt={appName}
                   className="max-w-20 max-h-20 object-contain"
                 />
@@ -890,7 +895,7 @@ export default function LoginPage() {
           <div className="px-8 pt-10 pb-6 text-center">
             <div className={cn("inline-flex items-center justify-center mb-5", !hasLogoSize && "w-16 h-16")}>
               <img
-                src={withBasePath(resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl)}
+                src={withBasePath(effLoginLogo)}
                 alt={appName}
                 className={cn("object-contain", !hasLogoSize && "max-w-16 max-h-16")}
                 style={loginLogoStyle}
diff --git a/components/layout/navigation-rail.tsx b/components/layout/navigation-rail.tsx
index f2bade53..a6fb1923 100644
--- a/components/layout/navigation-rail.tsx
+++ b/components/layout/navigation-rail.tsx
@@ -7,6 +7,7 @@ import { AccountSwitcher } from "./account-switcher";
 import { icons as lucideIcons, type LucideIcon } from "lucide-react";
 import { useConfig } from "@/hooks/use-config";
 import { useThemeStore } from "@/stores/theme-store";
+import { resolveThemeLogo } from "@/lib/theme-logo";
 import { usePathname, Link, useRouter } from "@/i18n/navigation";
 import { useTranslations } from "next-intl";
 import { useCalendarStore } from "@/stores/calendar-store";
@@ -190,6 +191,8 @@ export function NavigationRail({
   const router = useRouter();
   const { appLogoLightUrl, appLogoDarkUrl } = useConfig();
   const resolvedTheme = useThemeStore((s) => s.resolvedTheme);
+  const activeThemeId = useThemeStore((s) => s.activeThemeId);
+  const installedThemes = useThemeStore((s) => s.installedThemes);
   const { supportsCalendar } = useCalendarStore();
   const { mailboxes } = useEmailStore();
   const client = useAuthStore((s) => s.client);
@@ -462,7 +465,7 @@ export function NavigationRail({
       )}
     >
       {(() => {
-        const logoUrl = withBasePath(resolvedTheme === 'dark' ? (appLogoDarkUrl || appLogoLightUrl) : (appLogoLightUrl || appLogoDarkUrl));
+        const logoUrl = withBasePath(resolveThemeLogo(installedThemes, activeThemeId, resolvedTheme === 'dark', appLogoLightUrl, appLogoDarkUrl));
         return logoUrl ? (
           <div className="flex items-center justify-center py-3 px-1">
             <img
diff --git a/lib/builtin-themes.ts b/lib/builtin-themes.ts
index 9304d456..1c9f380f 100644
--- a/lib/builtin-themes.ts
+++ b/lib/builtin-themes.ts
@@ -1104,6 +1104,8 @@ export const BUILTIN_THEMES: InstalledTheme[] = [
     description: 'VNClagoon brand theme — deep navy with cyan accent, DM Sans + Syne',
     css: vnclagoonCSS,
     skin: vnclagoonSkin,
+    logoLightUrl: '/branding/vncmail-wordmark-on-light.svg',
+    logoDarkUrl: '/branding/vncmail-wordmark-on-dark.svg',
     variants: ['light', 'dark'],
     typography: { fontSans: '"DM Sans", system-ui, -apple-system, "Segoe UI", sans-serif' },
     enabled: true,
@@ -1116,6 +1118,8 @@ export const BUILTIN_THEMES: InstalledTheme[] = [
     author: 'VNC',
     description: 'SRC Advisory brand theme — Swiss red on white, light-first',
     css: srcCSS,
+    logoLightUrl: '/branding/src-logo.svg',
+    logoDarkUrl: '/branding/src-logo.svg',
     variants: ['light', 'dark'],
     enabled: true,
     builtIn: true,
diff --git a/lib/plugin-types.ts b/lib/plugin-types.ts
index b93543a1..769fe62e 100644
--- a/lib/plugin-types.ts
+++ b/lib/plugin-types.ts
@@ -204,6 +204,13 @@ export interface InstalledTheme {
    * lifecycle as `css` to keep localStorage small.
    */
   skin?: string;
+  /**
+   * Optional brand logos. When this theme is the active theme, these override
+   * the global login/app logo (a full brand skin, not just colours). Falls back
+   * to the configured global logo when unset.
+   */
+  logoLightUrl?: string;
+  logoDarkUrl?: string;
   variants: ThemeVariant[];
   enabled: boolean;
   builtIn: boolean;
diff --git a/lib/theme-logo.ts b/lib/theme-logo.ts
new file mode 100644
index 00000000..f1647811
--- /dev/null
+++ b/lib/theme-logo.ts
@@ -0,0 +1,24 @@
+import type { InstalledTheme } from './plugin-types';
+
+/**
+ * Resolve which logo to show. When the active theme carries brand logos
+ * (logoLightUrl/logoDarkUrl), those win — so switching theme switches the whole
+ * brand (VNClagoon wordmark ↔ SRC mark). Otherwise falls back to the globally
+ * configured logo. Returns a raw path; the caller applies withBasePath().
+ */
+export function resolveThemeLogo(
+  themes: InstalledTheme[],
+  activeThemeId: string | null,
+  isDark: boolean,
+  fallbackLight: string,
+  fallbackDark: string,
+): string {
+  const theme = activeThemeId ? themes.find((t) => t.id === activeThemeId) : undefined;
+  if (theme) {
+    const themed = isDark
+      ? (theme.logoDarkUrl ?? theme.logoLightUrl)
+      : (theme.logoLightUrl ?? theme.logoDarkUrl);
+    if (themed) return themed;
+  }
+  return isDark ? (fallbackDark || fallbackLight) : (fallbackLight || fallbackDark);
+}
diff --git a/vnc/VNC-CHANGES.md b/vnc/VNC-CHANGES.md
index 23f17dae..c394a4bb 100644
--- a/vnc/VNC-CHANGES.md
+++ b/vnc/VNC-CHANGES.md
@@ -32,6 +32,11 @@ that merging new upstream releases stays a triage exercise, not an archaeology d
 | 2026-08-03 | `stores/theme-store.ts` | default `theme`/`resolvedTheme` → `dark` | dark-first per VNClagoon styleguide |
 | 2026-08-03 | `lib/builtin-themes.ts` | add `builtin-src` theme (Swiss red on white, light-first) | 2nd brand theme (SRC Advisory); VNClagoon stays default |
 | 2026-08-03 | `public/branding/src-logo.svg` (new) | SRC mountain mark | SRC brand (placeholder — swap official) |
+| 2026-08-03 | `lib/plugin-types.ts` | add optional `logoLightUrl`/`logoDarkUrl` to InstalledTheme | per-theme brand logos |
+| 2026-08-03 | `lib/theme-logo.ts` (new) | `resolveThemeLogo()` helper | pick active theme's logo, fall back to global |
+| 2026-08-03 | `lib/builtin-themes.ts` | set logos on vnclagoon (wordmark) + src (mark) | logo switches with the brand theme |
+| 2026-08-03 | `app/(main)/[locale]/login/page.tsx` | login logo uses active theme's logo | brand-switch on login |
+| 2026-08-03 | `components/layout/navigation-rail.tsx` | nav-rail logo uses active theme's logo | brand-switch in app |
 
 _Note: Vercel was tried and **abandoned** on 2026-08-03. Bulwark writes to a local
 data dir (`/app/data/*`); Vercel serverless has a read-only filesystem → crash