diff --git a/README.md b/README.md
index 673008b..275e185 100644
--- a/README.md
+++ b/README.md
@@ -452,6 +452,7 @@ interface DragDropAttributes {
 - **[Nested Containers](https://github.com/thisuxhq/SvelteDnD/blob/main/src/routes/nested/+page.svelte)**: Explore the example in `src/routes/nested/+page.svelte`.
 - **[Custom Classes](https://github.com/thisuxhq/SvelteDnD/blob/main/src/routes/custom-classes/+page.svelte)**: Explore the example in `src/routes/custom-classes/+page.svelte`.
 - **[Interactive Elements](https://github.com/thisuxhq/SvelteDnD/blob/main/src/routes/interactive-elements/+page.svelte)**: Explore the example in `src/routes/interactive-elements/+page.svelte`.
+- **[Conditional Check](https://github.com/thisuxhq/SvelteDnD/blob/main/src/routes/conditional-check/+page.svelte)**: Explore the example in `src/routes/conditional-check/+page.svelte`.
 
 ## Styling
 
diff --git a/package.json b/package.json
index 200f6cc..9bfabe2 100644
--- a/package.json
+++ b/package.json
@@ -75,6 +75,6 @@
 		"vitest": "^2.0.4"
 	},
 	"dependencies": {
-		"@thisux/sveltednd": "^0.0.14"
+		"@thisux/sveltednd": "^0.0.17"
 	}
 }
\ No newline at end of file
diff --git a/src/lib/stores/dnd.svelte.ts b/src/lib/stores/dnd.svelte.ts
index fcc6d7b..2e4aed8 100644
--- a/src/lib/stores/dnd.svelte.ts
+++ b/src/lib/stores/dnd.svelte.ts
@@ -6,5 +6,6 @@ export const dndState = $state<DragDropState>({
 	draggedItem: null,
 	sourceContainer: '',
 	targetContainer: null,
-	targetElement: null
+	targetElement: null,
+	invalidDrop: false
 });
diff --git a/src/lib/types/index.ts b/src/lib/types/index.ts
index 7c9a610..9cc170f 100644
--- a/src/lib/types/index.ts
+++ b/src/lib/types/index.ts
@@ -4,6 +4,7 @@ export interface DragDropState<T = unknown> {
 	sourceContainer: string;
 	targetContainer: string | null;
 	targetElement: HTMLElement | null;
+	invalidDrop?: boolean;
 }
 
 export interface DragDropCallbacks<T = unknown> {
diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index 57292bc..0055650 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -12,85 +12,71 @@
 		{ path: '/nested', title: 'Nested Containers' },
 		{ path: '/multiple', title: 'Multiple' },
 		{ path: '/custom-classes', title: 'Custom Classes' },
-		{ path: '/interactive-elements', title: 'Interactives' }
+		{ path: '/interactive-elements', title: 'Interactives' },
+		{ path: '/conditional-check', title: 'Conditional Check' }
 	];
 
 	const cn = (...classes: string[]) => classes.filter(Boolean).join(' ');
 </script>
 
-<div class="mx-auto min-h-screen w-full bg-gray-100">
-	<div class="flex flex-col">
-		<nav class="hidden border-b bg-white px-8 py-4 md:sticky md:top-0 md:block">
-			<div class="flex items-center justify-between">
-				<div class="flex gap-4 overflow-x-auto whitespace-nowrap">
-					<div class="flex-1 overflow-hidden">
-						<div class="flex gap-4 overflow-x-auto whitespace-nowrap">
-							{#each examples as { path, title }}
-								<a
-									href={path}
-									class={cn(
-										'rounded px-3 py-1 text-sm hover:bg-gray-100',
-										$page.url.pathname === path ? 'text-primary rounded-md bg-gray-100' : ''
-									)}
-								>
-									{title}
-								</a>
-							{/each}
-						</div>
-					</div>
-				</div>
-				<div class="flex gap-2">
-					<a
-						href="https://github.com/thisuxhq/sveltednd"
-						class="flex items-center gap-2 rounded-md bg-[#24292e] px-4 py-2 text-sm text-white hover:bg-[#1b1f23]"
-						target="_blank"
-						rel="noopener noreferrer"
+<div class="flex min-h-screen bg-gray-100">
+	<!-- Sidebar -->
+	<aside class="hidden w-64 border-r bg-white md:block">
+		<div class="flex h-full flex-col">
+			<!-- Logo section -->
+			<div class="border-b p-4">
+				<div class="flex flex-col space-y-1">
+					<h1 class="text-primary text-xl font-semibold">SvelteDnD</h1>
+					<a href="https://thisux.com" target="_blank" class="hover:text-primary text-xs"
+						>by ThisUX</a
 					>
-						<svg class="h-4 w-4" viewBox="0 0 24 24" fill="currentColor">
-							<path
-								d="M12 0c-6.626 0-12 5.373-12 12 0 5.302 3.438 9.8 8.207 11.387.599.111.793-.261.793-.577v-2.234c-3.338.726-4.033-1.416-4.033-1.416-.546-1.387-1.333-1.756-1.333-1.756-1.089-.745.083-.729.083-.729 1.205.084 1.839 1.237 1.839 1.237 1.07 1.834 2.807 1.304 3.492.997.107-.775.418-1.305.762-1.604-2.665-.305-5.467-1.334-5.467-5.931 0-1.311.469-2.381 1.236-3.221-.124-.303-.535-1.524.117-3.176 0 0 1.008-.322 3.301 1.23.957-.266 1.983-.399 3.003-.404 1.02.005 2.047.138 3.006.404 2.291-1.552 3.297-1.23 3.297-1.23.653 1.653.242 2.874.118 3.176.77.84 1.235 1.911 1.235 3.221 0 4.609-2.807 5.624-5.479 5.921.43.372.823 1.102.823 2.222v3.293c0 .319.192.694.801.576 4.765-1.589 8.199-6.086 8.199-11.386 0-6.627-5.373-12-12-12z"
-							/>
-						</svg>
-						GitHub
-					</a>
+				</div>
+			</div>
+
+			<!-- Navigation links -->
+			<div class="flex-1 overflow-y-auto p-4">
+				{#each examples as { path, title }}
 					<a
-						href="https://www.npmjs.com/package/@thisux/sveltednd"
-						class="flex items-center gap-2 rounded-md bg-[#cb3837] px-4 py-2 text-sm text-white hover:bg-[#ab3231]"
-						target="_blank"
-						rel="noopener noreferrer"
+						href={path}
+						class={cn(
+							'block rounded px-3 py-2 text-sm font-medium transition-colors',
+							'hover:text-primary hover:bg-gray-100',
+							$page.url.pathname === path ? 'text-primary bg-gray-100' : 'text-gray-600'
+						)}
 					>
-						<svg class="h-4 w-4" viewBox="0 0 24 24" fill="currentColor">
-							<path
-								d="M0 7.334v8h6.666v1.332H12v-1.332h12v-8H0zm6.666 6.664H5.334v-4H3.999v4H1.335V8.667h5.331v5.331zm4 0v1.336H8.001V8.667h5.334v5.332h-2.669v-.001zm12.001 0h-1.33v-4h-1.336v4h-1.335v-4h-1.33v4h-2.671V8.667h8.002v5.331zM10.665 10H12v2.667h-1.335V10z"
-							/>
-						</svg>
-						NPM
+						{title}
 					</a>
-				</div>
+				{/each}
 			</div>
-		</nav>
+		</div>
+	</aside>
+
+	<!-- Main content -->
+	<div class="flex-1">
 		{@render children()}
-		<nav class="sticky bottom-0 border-t bg-white px-8 py-4 md:hidden">
+	</div>
+</div>
+
+<!-- Mobile bottom navigation -->
+<nav class="sticky bottom-0 border-t bg-white px-8 py-4 md:hidden">
+	<div class="flex gap-4 overflow-x-auto whitespace-nowrap">
+		<div class="flex-1 overflow-hidden">
 			<div class="flex gap-4 overflow-x-auto whitespace-nowrap">
-				<div class="flex-1 overflow-hidden">
-					<div class="flex gap-4 overflow-x-auto whitespace-nowrap">
-						{#each examples as { path, title }}
-							<a
-								href={path}
-								class={cn(
-									'rounded px-3 py-1 text-sm hover:bg-gray-100',
-									$page.url.pathname === path ? 'text-primary rounded-md bg-gray-100' : ''
-								)}
-							>
-								{title}
-							</a>
-						{/each}
-					</div>
-				</div>
+				{#each examples as { path, title }}
+					<a
+						href={path}
+						class={cn(
+							'rounded px-3 py-1 text-sm hover:bg-gray-100',
+							$page.url.pathname === path ? 'text-primary rounded-md bg-gray-100' : ''
+						)}
+					>
+						{title}
+					</a>
+				{/each}
 			</div>
-		</nav>
+		</div>
 	</div>
-</div>
+</nav>
 
 <!-- Floating badge (hidden on mobile)-->
 <footer class="fixed bottom-8 right-8 z-50 hidden md:block">
diff --git a/src/routes/conditional-check/+page.svelte b/src/routes/conditional-check/+page.svelte
new file mode 100644
index 0000000..01f7f35
--- /dev/null
+++ b/src/routes/conditional-check/+page.svelte
@@ -0,0 +1,146 @@
+<script lang="ts">
+	import { draggable, droppable } from '$lib/index.js';
+	import { dndState } from '$lib/stores/dnd.svelte.js';
+	import type { DragDropState } from '$lib/types/index.js';
+
+	interface Fruit {
+		id: string;
+		name: string;
+		color: string;
+	}
+
+	let sourceFruits = $state([
+		{ id: '1', name: 'Apple', color: 'Red' },
+		{ id: '2', name: 'Banana', color: 'Yellow' },
+		{ id: '3', name: 'Grapes', color: 'Green' },
+		{ id: '4', name: 'Orange', color: 'Orange' },
+		{ id: '5', name: 'Pineapple', color: 'Yellow' },
+		{ id: '6', name: 'Strawberry', color: 'Red' },
+		{ id: '7', name: 'Watermelon', color: 'Green' }
+	]);
+
+	let targetFruits = $state([]);
+
+	// Add a derived state for empty states
+	let isTargetEmpty = $derived(targetFruits.length === 0);
+	let isSourceEmpty = $derived(sourceFruits.length === 0);
+
+	// Validation function that sets invalidDrop state
+	function validateDrop(state: DragDropState<Fruit>) {
+		const fruit = state.draggedItem;
+		if (!fruit) return;
+
+		// Set invalidDrop based on the color condition
+		dndState.invalidDrop = fruit.color !== 'Red';
+	}
+
+	const dragDropCallbacks = {
+		onDragOver: (state: DragDropState<Fruit>) => {
+			validateDrop(state);
+		},
+		onDrop: async (state: DragDropState<Fruit>) => {
+			if (dndState.invalidDrop || !state.draggedItem) {
+				return; // Prevent invalid drops
+			}
+
+			// Move fruit to target container
+			sourceFruits = sourceFruits.filter((fruit) => fruit.id !== state.draggedItem.id);
+			targetFruits = [...targetFruits, state.draggedItem];
+		},
+		onDragEnd: () => {
+			// Reset invalidDrop state when drag ends
+			dndState.invalidDrop = false;
+		}
+	};
+</script>
+
+<div class="container mx-auto p-8">
+	<div class="mb-12 space-y-2">
+		<h1 class="text-3xl font-bold tracking-tight">Fruit Sorter</h1>
+		<p class="text-muted-foreground">
+			Drop the red fruits in the target zone. Other colors will be rejected.
+		</p>
+	</div>
+
+	<div class="grid gap-8 md:grid-cols-2">
+		<!-- Source Container -->
+		<div class="space-y-4">
+			<h2 class="text-sm font-medium uppercase tracking-wide text-muted-foreground">Available Fruits</h2>
+			<div
+				class="min-h-[400px] rounded-lg border bg-white p-4 shadow-sm transition-all"
+				use:droppable={{ container: 'source' }}
+			>
+				{#if isSourceEmpty}
+					<div class="flex h-full items-center justify-center">
+						<p class="text-muted-foreground">All fruits have been sorted</p>
+					</div>
+				{:else}
+					<div class="grid gap-2">
+						{#each sourceFruits as fruit}
+							<div
+								use:draggable={{ container: 'source', dragData: fruit }}
+								class={`group flex items-center justify-between rounded-md border p-3 shadow-sm transition-all hover:shadow
+									${fruit.color === 'Red' ? 'border-red-200 bg-red-50/50' : 'border-muted bg-muted/5'}`}
+							>
+								<span class="font-medium">{fruit.name}</span>
+								<span
+									class={`rounded px-2 py-1 text-xs
+									${fruit.color === 'Red' ? 'bg-red-100 text-red-700' : 'bg-muted/10 text-muted-foreground'}`}
+								>
+									{fruit.color}
+								</span>
+							</div>
+						{/each}
+					</div>
+				{/if}
+			</div>
+		</div>
+
+		<!-- Target Container -->
+		<div class="space-y-4">
+			<h2 class="text-sm font-medium uppercase tracking-wide text-muted-foreground">Red Fruits Only</h2>
+			<div
+				class={`min-h-[400px] rounded-lg border bg-white p-4 shadow-sm transition-all
+					${
+						dndState.isDragging
+							? dndState.invalidDrop
+								? 'border-red-500/50 bg-red-50/5'
+								: 'border-blue-500/50 bg-blue-50/5'
+							: ''
+					}`}
+					
+				use:droppable={{
+					container: 'target',
+					callbacks: dragDropCallbacks,
+					attributes: {
+						dragOverClass: dndState.invalidDrop ? 'invalid-drop' : 'valid-drop'
+					}
+				}}
+			>
+				{#if isTargetEmpty}
+					<div class="flex h-full items-center justify-center">
+						<p class="text-muted-foreground">Drop red fruits here</p>
+					</div>
+				{:else}
+					<div class="grid gap-2">
+						{#each targetFruits as fruit}
+							<div class="flex items-center justify-between rounded-md border-red-200 bg-red-50/50 p-3 shadow-sm">
+								<span class="font-medium">{fruit.name}</span>
+								<span class="rounded bg-red-100 px-2 py-1 text-xs text-red-700">{fruit.color}</span>
+							</div>
+						{/each}
+					</div>
+				{/if}
+			</div>
+		</div>
+	</div>
+</div>
+
+<style>
+	.valid-drop {
+		@apply border-blue-500/50 bg-blue-50/5 ring-2 ring-blue-500/20 ring-offset-2;
+	}
+	.invalid-drop {
+		@apply border-red-500/50 bg-red-50/5 ring-2 ring-red-500/20 ring-offset-2;
+	}
+</style>