diff --git a/src/app/(dashboard)/dashboard-shell.tsx b/src/app/(dashboard)/dashboard-shell.tsx
index c81e77e..b873a27 100644
--- a/src/app/(dashboard)/dashboard-shell.tsx
+++ b/src/app/(dashboard)/dashboard-shell.tsx
@@ -7,7 +7,9 @@ import { SiteHeader } from "@/components/site-header";
 import { SiteFooter } from "@/components/site-footer";
 import { SidebarProvider, SidebarInset } from "@/components/ui/sidebar";
 import { ThemeCustomizer, ThemeCustomizerTrigger } from "@/components/theme-customizer";
+import { PrefsInitializer } from "@/components/theme-customizer/prefs-initializer";
 import { useSidebarConfig } from "@/hooks/use-sidebar-config";
+import type { ThemePrefs } from "@/lib/appwrite/theme-prefs-actions";
 
 export type ShellUser = {
   id: string;
@@ -25,10 +27,12 @@ export function DashboardShell({
   user,
   company,
   children,
+  initialPrefs,
 }: {
   user: ShellUser;
   company: ShellCompany;
   children: React.ReactNode;
+  initialPrefs: ThemePrefs;
 }) {
   const [themeCustomizerOpen, setThemeCustomizerOpen] = React.useState(false);
   const { config } = useSidebarConfig();
@@ -44,6 +48,8 @@ export function DashboardShell({
       }
       className={config.collapsible === "none" ? "sidebar-none-mode" : ""}
     >
+      <PrefsInitializer prefs={initialPrefs} />
+
       {config.side === "left" ? (
         <>
           <AppSidebar
@@ -88,6 +94,7 @@ export function DashboardShell({
       <ThemeCustomizer
         open={themeCustomizerOpen}
         onOpenChange={setThemeCustomizerOpen}
+        initialPrefs={initialPrefs}
       />
     </SidebarProvider>
   );
diff --git a/src/app/(dashboard)/layout.tsx b/src/app/(dashboard)/layout.tsx
index 572292e..4f2ff30 100644
--- a/src/app/(dashboard)/layout.tsx
+++ b/src/app/(dashboard)/layout.tsx
@@ -2,6 +2,8 @@ import { redirect } from "next/navigation";
 
 import { getActiveContext } from "@/lib/appwrite/active-context";
 import { getLogoUrl } from "@/lib/appwrite/storage";
+import { createSessionClient } from "@/lib/appwrite/server";
+import type { ThemePrefs } from "@/lib/appwrite/theme-prefs-actions";
 import { DashboardShell } from "./dashboard-shell";
 
 export default async function DashboardLayout({
@@ -12,6 +14,14 @@ export default async function DashboardLayout({
   const ctx = await getActiveContext();
   if (!ctx) redirect("/onboarding");
 
+  let themePrefs: ThemePrefs = {};
+  try {
+    const { account } = await createSessionClient();
+    themePrefs = await account.getPrefs<ThemePrefs>();
+  } catch {
+    // use defaults if prefs unavailable
+  }
+
   const company = {
     id: ctx.tenantId,
     name: ctx.settings?.companyName ?? "Çalışma alanı",
@@ -24,7 +34,7 @@ export default async function DashboardLayout({
   };
 
   return (
-    <DashboardShell user={user} company={company}>
+    <DashboardShell user={user} company={company} initialPrefs={themePrefs}>
       {children}
     </DashboardShell>
   );
diff --git a/src/components/theme-customizer/index.tsx b/src/components/theme-customizer/index.tsx
index e0a2aaa..eb14914 100644
--- a/src/components/theme-customizer/index.tsx
+++ b/src/components/theme-customizer/index.tsx
@@ -6,8 +6,11 @@ import { Button } from '@/components/ui/button'
 import { Sheet, SheetContent, SheetDescription, SheetHeader, SheetTitle } from '@/components/ui/sheet'
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
 import { useThemeManager } from '@/hooks/use-theme-manager'
+import { useTheme } from '@/hooks/use-theme'
 import { useSidebarConfig } from '@/contexts/sidebar-context'
 import { tweakcnThemes } from '@/config/theme-data'
+import { saveThemePrefsAction } from '@/lib/appwrite/theme-prefs-actions'
+import type { ThemePrefs } from '@/lib/appwrite/theme-prefs-actions'
 import { ThemeTab } from './theme-tab'
 import { LayoutTab } from './layout-tab'
 import { ImportModal } from './import-modal'
@@ -17,37 +20,49 @@ import type { ImportedTheme } from '@/types/theme-customizer'
 interface ThemeCustomizerProps {
   open: boolean
   onOpenChange: (open: boolean) => void
+  initialPrefs: ThemePrefs
 }
 
-export function ThemeCustomizer({ open, onOpenChange }: ThemeCustomizerProps) {
+export function ThemeCustomizer({ open, onOpenChange, initialPrefs }: ThemeCustomizerProps) {
   const { applyImportedTheme, isDarkMode, resetTheme, applyRadius, setBrandColorsValues, applyTheme, applyTweakcnTheme } = useThemeManager()
+  const { theme } = useTheme()
   const { config: sidebarConfig, updateConfig: updateSidebarConfig } = useSidebarConfig()
 
   const [activeTab, setActiveTab] = React.useState("theme")
-  const [selectedTheme, setSelectedTheme] = React.useState("default")
-  const [selectedTweakcnTheme, setSelectedTweakcnTheme] = React.useState("")
-  const [selectedRadius, setSelectedRadius] = React.useState("0.5rem")
+  const [selectedTheme, setSelectedTheme] = React.useState(initialPrefs.colorTheme ?? "default")
+  const [selectedTweakcnTheme, setSelectedTweakcnTheme] = React.useState(initialPrefs.tweakcnTheme ?? "")
+  const [selectedRadius, setSelectedRadius] = React.useState(initialPrefs.radius ?? "0.5rem")
   const [importModalOpen, setImportModalOpen] = React.useState(false)
   const [importedTheme, setImportedTheme] = React.useState<ImportedTheme | null>(null)
 
-  const handleReset = () => {
-    // Complete reset to application defaults
+  // Save dark/light mode to Appwrite when it changes (skip first mount)
+  const themeMountRef = React.useRef(false)
+  React.useEffect(() => {
+    if (!themeMountRef.current) { themeMountRef.current = true; return }
+    void saveThemePrefsAction({ theme })
+  }, [theme])
 
-    // 1. Reset all state variables to initial values
+  // Save sidebar config to Appwrite when it changes (skip first mount)
+  const sidebarMountRef = React.useRef(false)
+  React.useEffect(() => {
+    if (!sidebarMountRef.current) { sidebarMountRef.current = true; return }
+    void saveThemePrefsAction({
+      sidebarVariant: sidebarConfig.variant,
+      sidebarCollapsible: sidebarConfig.collapsible,
+      sidebarSide: sidebarConfig.side,
+    })
+  }, [sidebarConfig.variant, sidebarConfig.collapsible, sidebarConfig.side])
+
+  const handleReset = () => {
     setSelectedTheme("default")
     setSelectedTweakcnTheme("")
     setSelectedRadius("0.5rem")
-    setImportedTheme(null) // Clear imported theme
-    setBrandColorsValues({}) // Clear brand colors state
-
-    // 2. Completely remove all custom CSS variables
+    setImportedTheme(null)
+    setBrandColorsValues({})
     resetTheme()
-
-    // 3. Reset the radius to default
     applyRadius("0.5rem")
-
-    // 4. Reset sidebar to defaults
     updateSidebarConfig({ variant: "inset", collapsible: "offcanvas", side: "left" })
+    void saveThemePrefsAction({ colorTheme: "default", tweakcnTheme: "", radius: "0.5rem" })
   }
 
   const handleImport = (themeData: ImportedTheme) => {
@@ -140,11 +155,22 @@ export function ThemeCustomizer({ open, onOpenChange }: ThemeCustomizerProps) {
               <TabsContent value="theme" className="flex-1 mt-0">
                 <ThemeTab
                   selectedTheme={selectedTheme}
-                  setSelectedTheme={setSelectedTheme}
+                  setSelectedTheme={(value) => {
+                    setSelectedTheme(value)
+                    setSelectedTweakcnTheme("")
+                    void saveThemePrefsAction({ colorTheme: value, tweakcnTheme: "" })
+                  }}
                   selectedTweakcnTheme={selectedTweakcnTheme}
-                  setSelectedTweakcnTheme={setSelectedTweakcnTheme}
+                  setSelectedTweakcnTheme={(value) => {
+                    setSelectedTweakcnTheme(value)
+                    setSelectedTheme("")
+                    void saveThemePrefsAction({ tweakcnTheme: value, colorTheme: "" })
+                  }}
                   selectedRadius={selectedRadius}
-                  setSelectedRadius={setSelectedRadius}
+                  setSelectedRadius={(value) => {
+                    setSelectedRadius(value)
+                    void saveThemePrefsAction({ radius: value })
+                  }}
                   setImportedTheme={setImportedTheme}
                   onImportClick={handleImportClick}
                 />
diff --git a/src/components/theme-customizer/prefs-initializer.tsx b/src/components/theme-customizer/prefs-initializer.tsx
new file mode 100644
index 0000000..93d2902
--- /dev/null
+++ b/src/components/theme-customizer/prefs-initializer.tsx
@@ -0,0 +1,51 @@
+"use client";
+
+import { useEffect, useRef } from "react";
+
+import { useSidebarConfig } from "@/contexts/sidebar-context";
+import { useTheme } from "@/hooks/use-theme";
+import { useThemeManager } from "@/hooks/use-theme-manager";
+import { tweakcnThemes } from "@/config/theme-data";
+import type { ThemePrefs } from "@/lib/appwrite/theme-prefs-actions";
+
+export function PrefsInitializer({ prefs }: { prefs: ThemePrefs }) {
+  const { setTheme } = useTheme();
+  const { updateConfig } = useSidebarConfig();
+  const { applyTheme, applyTweakcnTheme, applyRadius } = useThemeManager();
+  const applied = useRef(false);
+
+  useEffect(() => {
+    if (applied.current) return;
+    applied.current = true;
+
+    if (prefs.theme) setTheme(prefs.theme);
+
+    const isDark =
+      prefs.theme === "dark" ||
+      (prefs.theme !== "light" &&
+        typeof window !== "undefined" &&
+        window.matchMedia("(prefers-color-scheme: dark)").matches);
+
+    if (prefs.radius) applyRadius(prefs.radius);
+
+    if (prefs.colorTheme) {
+      applyTheme(prefs.colorTheme, isDark);
+    }
+
+    if (prefs.tweakcnTheme) {
+      const preset = tweakcnThemes.find((t) => t.value === prefs.tweakcnTheme)?.preset;
+      if (preset) applyTweakcnTheme(preset, isDark);
+    }
+
+    if (prefs.sidebarVariant || prefs.sidebarCollapsible || prefs.sidebarSide) {
+      updateConfig({
+        ...(prefs.sidebarVariant && { variant: prefs.sidebarVariant }),
+        ...(prefs.sidebarCollapsible && { collapsible: prefs.sidebarCollapsible }),
+        ...(prefs.sidebarSide && { side: prefs.sidebarSide }),
+      });
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
+  return null;
+}
diff --git a/src/lib/appwrite/theme-prefs-actions.ts b/src/lib/appwrite/theme-prefs-actions.ts
new file mode 100644
index 0000000..c5d20d0
--- /dev/null
+++ b/src/lib/appwrite/theme-prefs-actions.ts
@@ -0,0 +1,23 @@
+"use server";
+
+import { createSessionClient } from "@/lib/appwrite/server";
+
+export interface ThemePrefs {
+  theme?: "dark" | "light" | "system";
+  colorTheme?: string;
+  tweakcnTheme?: string;
+  radius?: string;
+  sidebarVariant?: "sidebar" | "floating" | "inset";
+  sidebarCollapsible?: "offcanvas" | "icon" | "none";
+  sidebarSide?: "left" | "right";
+}
+
+export async function saveThemePrefsAction(update: Partial<ThemePrefs>): Promise<void> {
+  try {
+    const { account } = await createSessionClient();
+    const existing = await account.getPrefs<Record<string, unknown>>();
+    await account.updatePrefs({ ...existing, ...update });
+  } catch {
+    // best-effort — UI still works without persistence
+  }
+}