diff --git a/src/lib/components/AuthModal.svelte b/src/lib/components/AuthModal.svelte
new file mode 100644
index 0000000..7cab036
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+++ b/src/lib/components/AuthModal.svelte
@@ -0,0 +1,217 @@
+<script lang="ts">
+	import { enhance } from '$app/forms';
+	import { browser } from '$app/environment';
+	import Container from './Container.svelte';
+
+	let { 
+		isOpen = $bindable(),
+		anonymousId = '' 
+	}: {
+		isOpen: boolean;
+		anonymousId: string;
+	} = $props();
+
+	let mode = $state<'signin' | 'signup'>('signin');
+	let loading = $state(false);
+	let error = $state('');
+	let success = $state('');
+
+	let email = $state('');
+	let password = $state('');
+	let firstName = $state('');
+	let lastName = $state('');
+
+	function resetForm() {
+		email = '';
+		password = '';
+		firstName = '';
+		lastName = '';
+		error = '';
+		success = '';
+	}
+
+	function switchMode() {
+		mode = mode === 'signin' ? 'signup' : 'signin';
+		resetForm();
+	}
+
+	function closeModal() {
+		isOpen = false;
+		resetForm();
+	}
+
+	function handleKeydown(event: KeyboardEvent) {
+		if (event.key === 'Escape') {
+			closeModal();
+		}
+	}
+
+	function handleSubmit() {
+		loading = true;
+		error = '';
+		success = '';
+	}
+
+	function handleResult(event: any) {
+		loading = false;
+		const result = event.result;
+		
+		if (result.type === 'success') {
+			if (result.data?.success) {
+				success = mode === 'signin' ? 'Signed in successfully!' : 'Account created successfully!';
+				setTimeout(() => {
+					if (browser) {
+						window.location.reload();
+					}
+				}, 1000);
+			} else if (result.data?.error) {
+				error = result.data.error;
+			}
+		} else if (result.type === 'failure') {
+			error = result.data?.error || 'An error occurred. Please try again.';
+		}
+	}
+</script>
+
+<svelte:window on:keydown={handleKeydown} />
+
+{#if isOpen}
+	<div class="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/70 backdrop-blur-sm">
+		<Container class="w-full max-w-md p-6 relative">
+			<button
+				type="button"
+				onclick={closeModal}
+				class="absolute top-4 right-4 text-white hover:text-gray-300 text-2xl leading-none"
+			>
+				×
+			</button>
+			<div class="mb-6">
+				<h2 class="text-2xl font-bold text-white">
+					{mode === 'signin' ? 'Sign In' : 'Create Account'}
+				</h2>
+			</div>
+
+			<form
+				method="POST"
+				action={mode === 'signin' ? '/auth/signin' : '/auth/signup'}
+				use:enhance={({ formData }) => {
+					if (mode === 'signup' && anonymousId) {
+						formData.append('anonymousId', anonymousId);
+					}
+					handleSubmit();
+					return handleResult;
+				}}
+			>
+				<div class="space-y-4">
+					{#if mode === 'signup'}
+						<div class="grid grid-cols-2 gap-4">
+							<div>
+								<label for="firstName" class="block text-sm font-medium text-white mb-1">
+									First Name
+								</label>
+								<input
+									id="firstName"
+									name="firstName"
+									type="text"
+									bind:value={firstName}
+									class="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-white bg-transparent placeholder-white/60"
+									placeholder="John"
+								/>
+							</div>
+							<div>
+								<label for="lastName" class="block text-sm font-medium text-white mb-1">
+									Last Name
+								</label>
+								<input
+									id="lastName"
+									name="lastName"
+									type="text"
+									bind:value={lastName}
+									class="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-white bg-transparent placeholder-white/60"
+									placeholder="Doe"
+								/>
+							</div>
+						</div>
+					{/if}
+
+					<div>
+						<label for="email" class="block text-sm font-medium text-white mb-1">
+							Email
+						</label>
+						<input
+							id="email"
+							name="email"
+							type="email"
+							required
+							bind:value={email}
+							class="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-white bg-transparent placeholder-white/60"
+							placeholder="john@example.com"
+						/>
+					</div>
+
+					<div>
+						<label for="password" class="block text-sm font-medium text-white mb-1">
+							Password
+						</label>
+						<input
+							id="password"
+							name="password"
+							type="password"
+							required
+							bind:value={password}
+							class="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-white bg-transparent placeholder-white/60"
+							placeholder="••••••••"
+							minlength="6"
+						/>
+						{#if mode === 'signup'}
+							<p class="text-xs text-white/80 mt-1">Minimum 6 characters</p>
+						{/if}
+					</div>
+				</div>
+
+				{#if error}
+					<div class="mt-4 p-3 bg-red-50 border border-red-200 rounded-md">
+						<p class="text-sm text-red-600">{error}</p>
+					</div>
+				{/if}
+
+				{#if success}
+					<div class="mt-4 p-3 bg-green-50 border border-green-200 rounded-md">
+						<p class="text-sm text-green-600">{success}</p>
+					</div>
+				{/if}
+
+				<button
+					type="submit"
+					disabled={loading}
+					class="w-full mt-6 px-4 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+				>
+					{#if loading}
+						<span class="inline-flex items-center">
+							<svg class="animate-spin -ml-1 mr-3 h-5 w-5 text-white" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24">
+								<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
+								<path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
+							</svg>
+							{mode === 'signin' ? 'Signing in...' : 'Creating account...'}
+						</span>
+					{:else}
+						{mode === 'signin' ? 'Sign In' : 'Create Account'}
+					{/if}
+				</button>
+			</form>
+
+			<div class="mt-6 text-center">
+				<p class="text-sm text-white">
+					{mode === 'signin' ? "Don't have an account?" : 'Already have an account?'}
+					<button
+						type="button"
+						onclick={switchMode}
+						class="text-blue-300 hover:text-blue-200 font-medium ml-1"
+					>
+						{mode === 'signin' ? 'Create one' : 'Sign in'}
+					</button>
+				</p>
+			</div>
+		</Container>
+	</div>
+{/if}
\ No newline at end of file