diff --git a/packages/cli/package.json b/packages/cli/package.json
index 4d146f14..8e23afb3 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@wrnexus/cli",
-  "version": "0.8.25",
+  "version": "0.8.26",
   "type": "module",
   "main": "src/index.ts",
   "exports": {
diff --git a/packages/dev-server/package.json b/packages/dev-server/package.json
index 20afc7c2..da8da609 100644
--- a/packages/dev-server/package.json
+++ b/packages/dev-server/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@wrnexus/dev-server",
-  "version": "0.8.24",
+  "version": "0.8.25",
   "type": "module",
   "main": "src/index.ts",
   "exports": {
diff --git a/packages/styles/package.json b/packages/styles/package.json
index 57e77b4b..95a4f61c 100644
--- a/packages/styles/package.json
+++ b/packages/styles/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@wrnexus/styles",
-  "version": "0.8.10",
+  "version": "0.8.11",
   "type": "module",
   "main": "src/index.ts",
   "exports": {
diff --git a/packages/styles/src/theme.ts b/packages/styles/src/theme.ts
index c5d2e42a..b226591e 100644
--- a/packages/styles/src/theme.ts
+++ b/packages/styles/src/theme.ts
@@ -98,6 +98,19 @@ export interface ThemeAccentConfig {
   default?: ThemePaletteName | false;
   /** Runtime-selectable accent names. Defaults to every built-in THEME_PALETTE. */
   options?: ThemePaletteName[];
+  /** Cookie scope used to persist the selected accent across related applications. */
+  cookie?: ThemeCookieConfig;
+}
+
+export interface ThemeCookieConfig {
+  /** Parent domain shared by related applications, for example `localhost` or `.example.com`. */
+  domain?: string;
+  /** Cookie path. Defaults to `/`. */
+  path?: string;
+  /** SameSite policy. Defaults to `Lax`. */
+  sameSite?: "Strict" | "Lax" | "None";
+  /** Force or disable Secure. When omitted it follows the current protocol. */
+  secure?: boolean;
 }
 
 export interface ThemeConfig {
@@ -117,6 +130,7 @@ export interface ResolvedTheme {
   themes: Record<string, ThemeTokens>;
   defaultAccent?: ThemePaletteName;
   accentNames: ThemePaletteName[];
+  accentCookie?: ThemeCookieConfig;
 }
 
 /** Cookies used by the SSR renderer and client runtime. */
@@ -494,6 +508,7 @@ export function resolveThemeConfig(config?: ThemeConfig): ResolvedTheme {
     themes,
     defaultAccent,
     accentNames,
+    accentCookie: config?.accent?.cookie,
   };
 }
 
@@ -622,6 +637,7 @@ export function renderThemeRuntime(theme: ResolvedTheme): string {
   const accentNames = JSON.stringify(theme.accentNames);
   const defaultAccent = JSON.stringify(theme.defaultAccent ?? null);
   const cssPrefix = JSON.stringify(THEME_CSS_PREFIX);
+  const accentCookie = JSON.stringify(theme.accentCookie ?? {});
 
   return `(function(){
   var THEME_COOKIE=${JSON.stringify(THEME_COOKIE)};
@@ -631,6 +647,7 @@ export function renderThemeRuntime(theme: ResolvedTheme): string {
   var DEFAULT_THEME=${JSON.stringify(theme.default)};
   var DEFAULT_ACCENT=${defaultAccent};
   var THEME_CSS_PREFIX=${cssPrefix};
+  var ACCENT_COOKIE_OPTIONS=${accentCookie};
   var MAX_AGE=31536000;
   var el=document.documentElement;
 
@@ -646,15 +663,22 @@ export function renderThemeRuntime(theme: ResolvedTheme): string {
     return null;
   }
 
-  function writeCookie(name,value){
-    var secure=location.protocol==="https:"?";secure":"";
-    document.cookie=encodeURIComponent(name)+"="+encodeURIComponent(value)+
-      ";path=/;max-age="+MAX_AGE+";samesite=lax"+secure;
+  function cookieOptions(options){
+    options=options||{};
+    var path=options.path||"/";
+    var sameSite=options.sameSite||"Lax";
+    var domain=options.domain?";domain="+options.domain:"";
+    var secure=options.secure===true||(options.secure!==false&&location.protocol==="https:")?";secure":"";
+    return ";path="+path+";samesite="+sameSite+domain+secure;
   }
 
-  function deleteCookie(name){
-    var secure=location.protocol==="https:"?";secure":"";
-    document.cookie=encodeURIComponent(name)+"=;path=/;max-age=0;samesite=lax"+secure;
+  function writeCookie(name,value,options){
+    document.cookie=encodeURIComponent(name)+"="+encodeURIComponent(value)+
+      ";max-age="+MAX_AGE+cookieOptions(options);
+  }
+
+  function deleteCookie(name,options){
+    document.cookie=encodeURIComponent(name)+"=;max-age=0"+cookieOptions(options);
   }
 
   function syncStylesheet(themeName,accentName){
@@ -705,7 +729,8 @@ export function renderThemeRuntime(theme: ResolvedTheme): string {
   function setAccent(name){
     if(ACCENTS.indexOf(name)<0)return;
     el.setAttribute("data-accent",name);
-    writeCookie(ACCENT_COOKIE,name);
+    deleteCookie(ACCENT_COOKIE);
+    writeCookie(ACCENT_COOKIE,name,ACCENT_COOKIE_OPTIONS);
     syncStylesheet(getTheme(),name);
     syncAccentButtons(document);
     window.dispatchEvent(new CustomEvent("wrnexus:accent-changed",{detail:{accent:name}}));
@@ -714,6 +739,7 @@ export function renderThemeRuntime(theme: ResolvedTheme): string {
   function clearAccent(){
     el.removeAttribute("data-accent");
     deleteCookie(ACCENT_COOKIE);
+    deleteCookie(ACCENT_COOKIE,ACCENT_COOKIE_OPTIONS);
     syncStylesheet(getTheme(),null);
     syncAccentButtons(document);
     window.dispatchEvent(new CustomEvent("wrnexus:accent-changed",{detail:{accent:null}}));
diff --git a/packages/styles/test/theme-accent.test.ts b/packages/styles/test/theme-accent.test.ts
index 310942fc..d78b9a74 100644
--- a/packages/styles/test/theme-accent.test.ts
+++ b/packages/styles/test/theme-accent.test.ts
@@ -46,6 +46,19 @@ describe("theme accents", () => {
     expect(runtime).not.toContain("localStorage");
     expect(runtime).not.toContain("style.setProperty");
   });
+
+  test("runtime scopes accent cookies to a configured parent domain", () => {
+    const theme = resolveThemeConfig({
+      palette: "rose",
+      accent: { cookie: { domain: "localhost", path: "/", sameSite: "Lax", secure: false } },
+    });
+    const runtime = renderThemeRuntime(theme);
+
+    expect(theme.accentCookie?.domain).toBe("localhost");
+    expect(runtime).toContain('"domain":"localhost"');
+    expect(runtime).toContain("deleteCookie(ACCENT_COOKIE);");
+    expect(runtime).toContain("writeCookie(ACCENT_COOKIE,name,ACCENT_COOKIE_OPTIONS)");
+  });
 });
 test("live document accent has priority over cookie and default", () => {
   const runtime = renderThemeRuntime(