diff --git a/src/lib/components/ui/avatar/avatar-fallback.svelte b/src/lib/components/ui/avatar/avatar-fallback.svelte
new file mode 100644
index 0000000..249d4a4
--- /dev/null
+++ b/src/lib/components/ui/avatar/avatar-fallback.svelte
@@ -0,0 +1,17 @@
+<script lang="ts">
+	import { Avatar as AvatarPrimitive } from "bits-ui";
+	import { cn } from "$lib/utils.js";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		...restProps
+	}: AvatarPrimitive.FallbackProps = $props();
+</script>
+
+<AvatarPrimitive.Fallback
+	bind:ref
+	data-slot="avatar-fallback"
+	class={cn("bg-muted flex size-full items-center justify-center rounded-full", className)}
+	{...restProps}
+/>
diff --git a/src/lib/components/ui/avatar/avatar-image.svelte b/src/lib/components/ui/avatar/avatar-image.svelte
new file mode 100644
index 0000000..2bb9db4
--- /dev/null
+++ b/src/lib/components/ui/avatar/avatar-image.svelte
@@ -0,0 +1,17 @@
+<script lang="ts">
+	import { Avatar as AvatarPrimitive } from "bits-ui";
+	import { cn } from "$lib/utils.js";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		...restProps
+	}: AvatarPrimitive.ImageProps = $props();
+</script>
+
+<AvatarPrimitive.Image
+	bind:ref
+	data-slot="avatar-image"
+	class={cn("aspect-square size-full", className)}
+	{...restProps}
+/>
diff --git a/src/lib/components/ui/avatar/avatar.svelte b/src/lib/components/ui/avatar/avatar.svelte
new file mode 100644
index 0000000..e37214d
--- /dev/null
+++ b/src/lib/components/ui/avatar/avatar.svelte
@@ -0,0 +1,19 @@
+<script lang="ts">
+	import { Avatar as AvatarPrimitive } from "bits-ui";
+	import { cn } from "$lib/utils.js";
+
+	let {
+		ref = $bindable(null),
+		loadingStatus = $bindable("loading"),
+		class: className,
+		...restProps
+	}: AvatarPrimitive.RootProps = $props();
+</script>
+
+<AvatarPrimitive.Root
+	bind:ref
+	bind:loadingStatus
+	data-slot="avatar"
+	class={cn("relative flex size-8 shrink-0 overflow-hidden rounded-full", className)}
+	{...restProps}
+/>
diff --git a/src/lib/components/ui/avatar/index.ts b/src/lib/components/ui/avatar/index.ts
new file mode 100644
index 0000000..d06457b
--- /dev/null
+++ b/src/lib/components/ui/avatar/index.ts
@@ -0,0 +1,13 @@
+import Root from "./avatar.svelte";
+import Image from "./avatar-image.svelte";
+import Fallback from "./avatar-fallback.svelte";
+
+export {
+	Root,
+	Image,
+	Fallback,
+	//
+	Root as Avatar,
+	Image as AvatarImage,
+	Fallback as AvatarFallback,
+};
diff --git a/src/lib/components/ui/switch/index.ts b/src/lib/components/ui/switch/index.ts
new file mode 100644
index 0000000..f5533db
--- /dev/null
+++ b/src/lib/components/ui/switch/index.ts
@@ -0,0 +1,7 @@
+import Root from "./switch.svelte";
+
+export {
+	Root,
+	//
+	Root as Switch,
+};
diff --git a/src/lib/components/ui/switch/switch.svelte b/src/lib/components/ui/switch/switch.svelte
new file mode 100644
index 0000000..80661fd
--- /dev/null
+++ b/src/lib/components/ui/switch/switch.svelte
@@ -0,0 +1,29 @@
+<script lang="ts">
+	import { Switch as SwitchPrimitive } from "bits-ui";
+	import { cn, type WithoutChildrenOrChild } from "$lib/utils.js";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		checked = $bindable(false),
+		...restProps
+	}: WithoutChildrenOrChild<SwitchPrimitive.RootProps> = $props();
+</script>
+
+<SwitchPrimitive.Root
+	bind:ref
+	bind:checked
+	data-slot="switch"
+	class={cn(
+		"data-[state=checked]:bg-primary data-[state=unchecked]:bg-input focus-visible:border-ring focus-visible:ring-ring/50 dark:data-[state=unchecked]:bg-input/80 peer inline-flex h-[1.15rem] w-8 shrink-0 items-center rounded-full border border-transparent shadow-xs transition-all outline-none focus-visible:ring-[3px] disabled:cursor-not-allowed disabled:opacity-50",
+		className
+	)}
+	{...restProps}
+>
+	<SwitchPrimitive.Thumb
+		data-slot="switch-thumb"
+		class={cn(
+			"bg-background dark:data-[state=unchecked]:bg-foreground dark:data-[state=checked]:bg-primary-foreground pointer-events-none block size-4 rounded-full ring-0 transition-transform data-[state=checked]:translate-x-[calc(100%-2px)] data-[state=unchecked]:translate-x-0"
+		)}
+	/>
+</SwitchPrimitive.Root>
diff --git a/src/routes/+layout.server.ts b/src/routes/+layout.server.ts
new file mode 100644
index 0000000..7d98a1b
--- /dev/null
+++ b/src/routes/+layout.server.ts
@@ -0,0 +1,7 @@
+import type { LayoutServerLoad } from './$types';
+
+export const load: LayoutServerLoad = async ({ locals }) => {
+	return {
+		user: locals.user ? structuredClone(locals.user) : null
+	};
+};
diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index 35c1c75..8a07009 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -1,13 +1,56 @@
 <script lang="ts">
 	import { onMount } from 'svelte';
+	import { goto } from '$app/navigation';
+	import { page } from '$app/stores';
 	import { Toaster } from 'svelte-sonner';
 	import './app.css';
 	import favicon from '$lib/assets/favicon.svg';
 	import { initRealtime } from '$lib/realtime';
+	import * as Avatar from '$lib/components/ui/avatar/index.js';
+	import * as DropdownMenu from '$lib/components/ui/dropdown-menu/index.js';
+	import { Switch } from '$lib/components/ui/switch/index.js';
+	import LogOutIcon from '@lucide/svelte/icons/log-out';
+	import MoonIcon from '@lucide/svelte/icons/moon';
 
-	let { children } = $props();
+	let { data, children } = $props();
 	let cleanupRealtime: (() => void) | undefined;
 
+	let darkmode = $state<boolean>((data.user as { darkmode?: boolean } | null)?.darkmode ?? false);
+
+	$effect(() => {
+		const root = typeof document !== 'undefined' ? document.documentElement : null;
+		if (root) root.classList.toggle('dark', darkmode);
+	});
+
+	async function toggleDarkmode(checked: boolean) {
+		darkmode = checked;
+		try {
+			await fetch('/api/user/settings', {
+				method: 'PATCH',
+				headers: { 'Content-Type': 'application/json' },
+				body: JSON.stringify({ darkmode: checked })
+			});
+		} catch {
+			darkmode = !checked;
+		}
+	}
+
+	function getInitials(user: { name?: string; email?: string } | null): string {
+		if (!user) return '?';
+		if (user.name && typeof user.name === 'string') {
+			const parts = user.name.trim().split(/\s+/);
+			if (parts.length >= 2) return (parts[0][0] + parts[parts.length - 1][0]).toUpperCase();
+			if (parts[0]) return parts[0].slice(0, 2).toUpperCase();
+		}
+		const email = user.email && typeof user.email === 'string' ? user.email : '';
+		const local = email.split('@')[0] ?? '';
+		if (local.length >= 2) return local.slice(0, 2).toUpperCase();
+		return local ? local[0].toUpperCase() : '?';
+	}
+
+	const showHeader = $derived(!!data.user && $page.url.pathname !== '/login');
+	const user = $derived(data.user);
+
 	onMount(() => {
 		let cancelled = false;
 		initRealtime().then((cleanup) => {
@@ -34,4 +77,49 @@
 	}}
 />
 
+{#if showHeader}
+	<header class="border-border flex h-14 shrink-0 items-center justify-end gap-2 border-b px-4 md:px-6">
+		<DropdownMenu.Root>
+			<DropdownMenu.Trigger
+				class="rounded-full outline-none focus-visible:ring-2 focus-visible:ring-ring"
+				asChild
+			>
+				<button type="button" class="rounded-full ring-offset-background focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2">
+					<Avatar.Root class="size-9">
+						<Avatar.Image
+							src={(user as { avatar?: string })?.avatar}
+							alt={(user as { name?: string })?.name ?? 'User'}
+						/>
+						<Avatar.Fallback class="bg-primary text-primary-foreground text-sm font-medium">
+							{getInitials(user as { name?: string; email?: string })}
+						</Avatar.Fallback>
+					</Avatar.Root>
+				</button>
+			</DropdownMenu.Trigger>
+			<DropdownMenu.Content align="end" class="w-56">
+				<div class="flex items-center justify-between gap-2 px-2 py-1.5 text-sm">
+					<span class="text-muted-foreground flex items-center gap-2">
+						<MoonIcon class="size-4" />
+						Dark mode
+					</span>
+					<Switch
+						checked={darkmode}
+						onCheckedChange={toggleDarkmode}
+					/>
+				</div>
+				<DropdownMenu.Separator />
+				<DropdownMenu.Item
+					onclick={async () => {
+						await fetch('/logout', { method: 'POST', credentials: 'same-origin' });
+						goto('/login');
+					}}
+				>
+					<LogOutIcon class="size-4" />
+					Log out
+				</DropdownMenu.Item>
+			</DropdownMenu.Content>
+		</DropdownMenu.Root>
+	</header>
+{/if}
+
 {@render children()}
diff --git a/src/routes/api/user/settings/+server.ts b/src/routes/api/user/settings/+server.ts
new file mode 100644
index 0000000..59150c0
--- /dev/null
+++ b/src/routes/api/user/settings/+server.ts
@@ -0,0 +1,24 @@
+import { json } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+
+export const PATCH: RequestHandler = async ({ locals, request }) => {
+	if (!locals.user) {
+		return json({ error: 'Unauthorized' }, { status: 401 });
+	}
+	let body: { darkmode?: boolean };
+	try {
+		body = await request.json();
+	} catch {
+		return json({ error: 'Invalid JSON' }, { status: 400 });
+	}
+	if (typeof body.darkmode !== 'boolean') {
+		return json({ error: 'darkmode must be a boolean' }, { status: 400 });
+	}
+	try {
+		await locals.pb.collection('users').update(locals.user.id, { darkmode: body.darkmode });
+		return json({ ok: true, darkmode: body.darkmode });
+	} catch (e) {
+		console.error('Failed to update user settings:', e);
+		return json({ error: 'Failed to update settings' }, { status: 500 });
+	}
+};
diff --git a/src/routes/logout/+server.ts b/src/routes/logout/+server.ts
new file mode 100644
index 0000000..e73422d
--- /dev/null
+++ b/src/routes/logout/+server.ts
@@ -0,0 +1,11 @@
+import { redirect } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+
+export const POST: RequestHandler = async ({ locals }) => {
+	locals.pb.authStore.clear();
+	return redirect(303, '/login', {
+		headers: {
+			'set-cookie': locals.pb.authStore.exportToCookie({ httpOnly: false, sameSite: 'Lax' })
+		}
+	});
+};