diff --git a/app/form/layout.tsx b/app/form/layout.tsx
index 30a7191..78f73c0 100644
--- a/app/form/layout.tsx
+++ b/app/form/layout.tsx
@@ -3,6 +3,8 @@ import { authOptions } from "@/app/api/auth/[...nextauth]/route";
 import { FormLayoutClient } from "./client";
 import LoginDialog from "@/components/login-dialog";
 import { Metadata } from "next";
+import { ThemeToggle } from "@/components/theme-toggle";
+import Link from 'next/link';
 
 const siteUrl = process.env.BASE_URL;
 
@@ -38,17 +40,22 @@ export default async function FormLayout({
   const session = await getServerSession(authOptions);
 
   return (
-    <div className="flex min-h-screen flex-col flex-1 w-full bg-background text-foreground dark">
+    <div className="flex min-h-screen flex-col flex-1 w-full bg-background text-foreground">
       <header className="border-b border-border px-6 py-3 flex items-center justify-between shrink-0">
-        <span className="font-semibold text-sm">
-          ฟอร์ม
-        </span>
-        {session?.user && (
-          <FormLayoutClient
-            userName={session.user.name ?? ""}
-            userImage={session.user.image ?? ""}
-          />
-        )}
+        <Link href="/form">
+          <span className="font-semibold text-sm">
+            Form
+          </span>
+        </Link>
+        <div className="flex items-center gap-2">
+          {session?.user && (
+            <FormLayoutClient
+              userName={session.user.name ?? ""}
+              userImage={session.user.image ?? ""}
+            />
+          )}
+          <ThemeToggle />
+        </div>
       </header>
       <main className="flex-1 p-6 md:p-8 overflow-y-auto max-w-6xl mx-auto w-full">
         {children}
diff --git a/app/layout.tsx b/app/layout.tsx
index 9d1d1e5..90539ed 100644
--- a/app/layout.tsx
+++ b/app/layout.tsx
@@ -71,6 +71,7 @@ export const metadata: Metadata = {
 
 import { TooltipProvider } from "@/components/ui/tooltip";
 import { Toaster } from "sonner";
+import { ThemeProvider } from "@/components/theme-provider";
 
 export default function RootLayout({
   children,
@@ -80,13 +81,21 @@ export default function RootLayout({
   return (
     <html
       lang="th"
-      className={cn("h-full", "dark", "antialiased", anuphan.variable, geistSans.variable, "font-sans")}
+      className={cn("h-full", "antialiased", anuphan.variable, geistSans.variable, "font-sans")}
+      suppressHydrationWarning
     >
       <body className={`${anuphan.className} ${geistSans.className}`}>
+        <ThemeProvider
+          attribute="class"
+          defaultTheme="system"
+          enableSystem
+          disableTransitionOnChange
+        >
         <TooltipProvider>
           <Toaster richColors closeButton position="bottom-right" theme="dark" toastOptions={{ className: anuphan.className }} />
           {children}
         </TooltipProvider>
+        </ThemeProvider>
       </body>
     </html>
   );
diff --git a/components/theme-provider.tsx b/components/theme-provider.tsx
new file mode 100644
index 0000000..34a9890
--- /dev/null
+++ b/components/theme-provider.tsx
@@ -0,0 +1,7 @@
+"use client"
+
+import { ThemeProvider as NextThemesProvider, type ThemeProviderProps } from "next-themes"
+
+export function ThemeProvider({ children, ...props }: ThemeProviderProps) {
+  return <NextThemesProvider {...props}>{children}</NextThemesProvider>
+}
diff --git a/components/theme-toggle.tsx b/components/theme-toggle.tsx
new file mode 100644
index 0000000..93560c7
--- /dev/null
+++ b/components/theme-toggle.tsx
@@ -0,0 +1,55 @@
+"use client"
+
+import * as React from "react"
+import { Moon, Sun, Monitor } from "lucide-react"
+import { useTheme } from "next-themes"
+
+import { Button } from "@/components/ui/button"
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu"
+
+export function ThemeToggle() {
+  const { setTheme, theme, resolvedTheme } = useTheme()
+  const [mounted, setMounted] = React.useState(false)
+
+  React.useEffect(() => {
+    setMounted(true)
+  }, [])
+
+  return (
+    <DropdownMenu>
+      <DropdownMenuTrigger asChild>
+        <Button variant="ghost" size="icon" className="w-9 h-9">
+          {!mounted ? (
+            <Sun className="h-[1.2rem] w-[1.2rem]" />
+          ) : theme === "system" ? (
+            <Monitor className="h-[1.2rem] w-[1.2rem]" />
+          ) : resolvedTheme === "dark" ? (
+            <Moon className="h-[1.2rem] w-[1.2rem]" />
+          ) : (
+            <Sun className="h-[1.2rem] w-[1.2rem]" />
+          )}
+          <span className="sr-only">Toggle theme</span>
+        </Button>
+      </DropdownMenuTrigger>
+      <DropdownMenuContent align="end">
+        <DropdownMenuItem onClick={() => setTheme("light")}>
+          <Sun className="mr-2 h-4 w-4" />
+          Light theme
+        </DropdownMenuItem>
+        <DropdownMenuItem onClick={() => setTheme("dark")}>
+          <Moon className="mr-2 h-4 w-4" />
+          Dark theme
+        </DropdownMenuItem>
+        <DropdownMenuItem onClick={() => setTheme("system")}>
+          <Monitor className="mr-2 h-4 w-4" />
+          System
+        </DropdownMenuItem>
+      </DropdownMenuContent>
+    </DropdownMenu>
+  )
+}
diff --git a/components/ui/dropdown-menu.tsx b/components/ui/dropdown-menu.tsx
new file mode 100644
index 0000000..172cc15
--- /dev/null
+++ b/components/ui/dropdown-menu.tsx
@@ -0,0 +1,269 @@
+"use client"
+
+import * as React from "react"
+import { DropdownMenu as DropdownMenuPrimitive } from "radix-ui"
+
+import { cn } from "@/lib/utils"
+import { CheckIcon, ChevronRightIcon } from "lucide-react"
+
+function DropdownMenu({
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Root>) {
+  return <DropdownMenuPrimitive.Root data-slot="dropdown-menu" {...props} />
+}
+
+function DropdownMenuPortal({
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Portal>) {
+  return (
+    <DropdownMenuPrimitive.Portal data-slot="dropdown-menu-portal" {...props} />
+  )
+}
+
+function DropdownMenuTrigger({
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Trigger>) {
+  return (
+    <DropdownMenuPrimitive.Trigger
+      data-slot="dropdown-menu-trigger"
+      {...props}
+    />
+  )
+}
+
+function DropdownMenuContent({
+  className,
+  align = "start",
+  sideOffset = 4,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Content>) {
+  return (
+    <DropdownMenuPrimitive.Portal>
+      <DropdownMenuPrimitive.Content
+        data-slot="dropdown-menu-content"
+        sideOffset={sideOffset}
+        align={align}
+        className={cn("z-50 max-h-(--radix-dropdown-menu-content-available-height) w-(--radix-dropdown-menu-trigger-width) min-w-48 origin-(--radix-dropdown-menu-content-transform-origin) overflow-x-hidden overflow-y-auto rounded-2xl bg-popover p-1 text-popover-foreground shadow-2xl ring-1 ring-foreground/5 duration-100 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 data-[state=closed]:overflow-hidden dark:ring-foreground/10 data-open:animate-in data-open:fade-in-0 data-open:zoom-in-95 data-closed:animate-out data-closed:fade-out-0 data-closed:zoom-out-95", className )}
+        {...props}
+      />
+    </DropdownMenuPrimitive.Portal>
+  )
+}
+
+function DropdownMenuGroup({
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Group>) {
+  return (
+    <DropdownMenuPrimitive.Group data-slot="dropdown-menu-group" {...props} />
+  )
+}
+
+function DropdownMenuItem({
+  className,
+  inset,
+  variant = "default",
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Item> & {
+  inset?: boolean
+  variant?: "default" | "destructive"
+}) {
+  return (
+    <DropdownMenuPrimitive.Item
+      data-slot="dropdown-menu-item"
+      data-inset={inset}
+      data-variant={variant}
+      className={cn(
+        "group/dropdown-menu-item relative flex cursor-default items-center gap-2.5 rounded-xl px-3 py-2 text-sm outline-hidden select-none focus:bg-accent focus:text-accent-foreground not-data-[variant=destructive]:focus:**:text-accent-foreground data-inset:pl-9.5 data-[variant=destructive]:text-destructive data-[variant=destructive]:focus:bg-destructive/10 data-[variant=destructive]:focus:text-destructive dark:data-[variant=destructive]:focus:bg-destructive/20 data-disabled:pointer-events-none data-disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4 data-[variant=destructive]:*:[svg]:text-destructive",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function DropdownMenuCheckboxItem({
+  className,
+  children,
+  checked,
+  inset,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.CheckboxItem> & {
+  inset?: boolean
+}) {
+  return (
+    <DropdownMenuPrimitive.CheckboxItem
+      data-slot="dropdown-menu-checkbox-item"
+      data-inset={inset}
+      className={cn(
+        "relative flex cursor-default items-center gap-2.5 rounded-xl py-2 pr-8 pl-3 text-sm outline-hidden select-none focus:bg-accent focus:text-accent-foreground focus:**:text-accent-foreground data-inset:pl-9.5 data-disabled:pointer-events-none data-disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
+        className
+      )}
+      checked={checked}
+      {...props}
+    >
+      <span
+        className="pointer-events-none absolute right-2 flex items-center justify-center"
+        data-slot="dropdown-menu-checkbox-item-indicator"
+      >
+        <DropdownMenuPrimitive.ItemIndicator>
+          <CheckIcon
+          />
+        </DropdownMenuPrimitive.ItemIndicator>
+      </span>
+      {children}
+    </DropdownMenuPrimitive.CheckboxItem>
+  )
+}
+
+function DropdownMenuRadioGroup({
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.RadioGroup>) {
+  return (
+    <DropdownMenuPrimitive.RadioGroup
+      data-slot="dropdown-menu-radio-group"
+      {...props}
+    />
+  )
+}
+
+function DropdownMenuRadioItem({
+  className,
+  children,
+  inset,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.RadioItem> & {
+  inset?: boolean
+}) {
+  return (
+    <DropdownMenuPrimitive.RadioItem
+      data-slot="dropdown-menu-radio-item"
+      data-inset={inset}
+      className={cn(
+        "relative flex cursor-default items-center gap-2.5 rounded-xl py-2 pr-8 pl-3 text-sm outline-hidden select-none focus:bg-accent focus:text-accent-foreground focus:**:text-accent-foreground data-inset:pl-9.5 data-disabled:pointer-events-none data-disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
+        className
+      )}
+      {...props}
+    >
+      <span
+        className="pointer-events-none absolute right-2 flex items-center justify-center"
+        data-slot="dropdown-menu-radio-item-indicator"
+      >
+        <DropdownMenuPrimitive.ItemIndicator>
+          <CheckIcon
+          />
+        </DropdownMenuPrimitive.ItemIndicator>
+      </span>
+      {children}
+    </DropdownMenuPrimitive.RadioItem>
+  )
+}
+
+function DropdownMenuLabel({
+  className,
+  inset,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Label> & {
+  inset?: boolean
+}) {
+  return (
+    <DropdownMenuPrimitive.Label
+      data-slot="dropdown-menu-label"
+      data-inset={inset}
+      className={cn(
+        "px-3 py-2.5 text-xs text-muted-foreground data-inset:pl-9.5",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function DropdownMenuSeparator({
+  className,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Separator>) {
+  return (
+    <DropdownMenuPrimitive.Separator
+      data-slot="dropdown-menu-separator"
+      className={cn("-mx-1 my-1 h-px bg-border/50", className)}
+      {...props}
+    />
+  )
+}
+
+function DropdownMenuShortcut({
+  className,
+  ...props
+}: React.ComponentProps<"span">) {
+  return (
+    <span
+      data-slot="dropdown-menu-shortcut"
+      className={cn(
+        "ml-auto text-xs tracking-widest text-muted-foreground group-focus/dropdown-menu-item:text-accent-foreground",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function DropdownMenuSub({
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.Sub>) {
+  return <DropdownMenuPrimitive.Sub data-slot="dropdown-menu-sub" {...props} />
+}
+
+function DropdownMenuSubTrigger({
+  className,
+  inset,
+  children,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.SubTrigger> & {
+  inset?: boolean
+}) {
+  return (
+    <DropdownMenuPrimitive.SubTrigger
+      data-slot="dropdown-menu-sub-trigger"
+      data-inset={inset}
+      className={cn(
+        "flex cursor-default items-center gap-2 rounded-xl px-3 py-2 text-sm outline-hidden select-none focus:bg-accent focus:text-accent-foreground not-data-[variant=destructive]:focus:**:text-accent-foreground data-inset:pl-9.5 data-open:bg-accent data-open:text-accent-foreground [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
+        className
+      )}
+      {...props}
+    >
+      {children}
+      <ChevronRightIcon className="ml-auto" />
+    </DropdownMenuPrimitive.SubTrigger>
+  )
+}
+
+function DropdownMenuSubContent({
+  className,
+  ...props
+}: React.ComponentProps<typeof DropdownMenuPrimitive.SubContent>) {
+  return (
+    <DropdownMenuPrimitive.SubContent
+      data-slot="dropdown-menu-sub-content"
+      className={cn("z-50 min-w-36 origin-(--radix-dropdown-menu-content-transform-origin) overflow-hidden rounded-2xl bg-popover p-1 text-popover-foreground shadow-2xl ring-1 ring-foreground/5 duration-100 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 data-open:animate-in data-open:fade-in-0 data-open:zoom-in-95 data-closed:animate-out data-closed:fade-out-0 data-closed:zoom-out-95", className )}
+      {...props}
+    />
+  )
+}
+
+export {
+  DropdownMenu,
+  DropdownMenuPortal,
+  DropdownMenuTrigger,
+  DropdownMenuContent,
+  DropdownMenuGroup,
+  DropdownMenuLabel,
+  DropdownMenuItem,
+  DropdownMenuCheckboxItem,
+  DropdownMenuRadioGroup,
+  DropdownMenuRadioItem,
+  DropdownMenuSeparator,
+  DropdownMenuShortcut,
+  DropdownMenuSub,
+  DropdownMenuSubTrigger,
+  DropdownMenuSubContent,
+}