diff --git a/src/lib/Editor.svelte b/src/lib/Editor.svelte
index c4b804e..9134817 100644
--- a/src/lib/Editor.svelte
+++ b/src/lib/Editor.svelte
@@ -40,10 +40,10 @@
 		editMode = modes[(idx + 1) % modes.length];
 	}
 
-	let htmlContainer: HTMLDivElement;
-	let cssContainer: HTMLDivElement;
-	let sharedContainer: HTMLDivElement;
-	let appContainer: HTMLDivElement;
+	let htmlContainer = $state<HTMLDivElement>(undefined!);
+	let cssContainer = $state<HTMLDivElement>(undefined!);
+	let sharedContainer = $state<HTMLDivElement>(undefined!);
+	let appContainer = $state<HTMLDivElement>(undefined!);
 
 	let htmlEditor: EditorView | null = null;
 	let cssEditor: EditorView | null = null;
diff --git a/src/lib/Palette.svelte b/src/lib/Palette.svelte
index 20871c5..0c79de5 100644
--- a/src/lib/Palette.svelte
+++ b/src/lib/Palette.svelte
@@ -1,24 +1,24 @@
 <script lang="ts">
 	import { Square, Type, Image, Music, Video, Globe } from 'lucide-svelte';
-	import { state } from './state.svelte';
+	import { state as appState } from './state.svelte';
 
-	let locked = $derived(state.locked);
+	let locked = $derived(appState.locked);
 
-	let imageInput: HTMLInputElement;
-	let soundInput: HTMLInputElement;
-	let videoInput: HTMLInputElement;
+	let imageInput = $state<HTMLInputElement>(undefined!);
+	let soundInput = $state<HTMLInputElement>(undefined!);
+	let videoInput = $state<HTMLInputElement>(undefined!);
 
 	function getSpawnPosition() {
 		return {
-			x: state.snap(-state.viewport.x / state.viewport.zoom + 400),
-			y: state.snap(-state.viewport.y / state.viewport.zoom + 300)
+			x: appState.snap(-appState.viewport.x / appState.viewport.zoom + 400),
+			y: appState.snap(-appState.viewport.y / appState.viewport.zoom + 300)
 		};
 	}
 
 	function addTile() {
 		const id = crypto.randomUUID();
 		const pos = getSpawnPosition();
-		state.addItem({
+		appState.addItem({
 			id,
 			html: '',
 			css: '',
@@ -27,15 +27,15 @@
 			width: 200,
 			height: 200,
 			rotation: 0,
-			zIndex: state.maxZIndex + 1
+			zIndex: appState.maxZIndex + 1
 		});
-		state.select(id);
+		appState.select(id);
 	}
 
 	function addText() {
 		const id = crypto.randomUUID();
 		const pos = getSpawnPosition();
-		state.addItem({
+		appState.addItem({
 			id,
 			html: '<p>Text</p>',
 			css: `p {
@@ -48,9 +48,9 @@
 			width: 200,
 			height: 50,
 			rotation: 0,
-			zIndex: state.maxZIndex + 1
+			zIndex: appState.maxZIndex + 1
 		});
-		state.select(id);
+		appState.select(id);
 	}
 
 	function addEmbed() {
@@ -58,7 +58,7 @@
 		if (!url) return;
 		const id = crypto.randomUUID();
 		const pos = getSpawnPosition();
-		state.addItem({
+		appState.addItem({
 			id,
 			html: `<iframe src="${url}" frameborder="0" allowfullscreen></iframe>`,
 			css: `iframe {
@@ -71,9 +71,9 @@
 			width: 640,
 			height: 480,
 			rotation: 0,
-			zIndex: state.maxZIndex + 1
+			zIndex: appState.maxZIndex + 1
 		});
-		state.select(id);
+		appState.select(id);
 	}
 
 	function handleImageChange(e: Event) {
@@ -105,8 +105,8 @@
 
 		const img = document.createElement('img');
 		img.onload = () => {
-			state.addAsset(assetId, { blob: file, url, filename: file.name });
-			state.addItem({
+			appState.addAsset(assetId, { blob: file, url, filename: file.name });
+			appState.addItem({
 				id,
 				assetId,
 				html: `<img src="${url}" alt="" />`,
@@ -120,9 +120,9 @@
 				width: img.naturalWidth,
 				height: img.naturalHeight,
 				rotation: 0,
-				zIndex: state.maxZIndex + 1
+				zIndex: appState.maxZIndex + 1
 			});
-			state.select(id);
+			appState.select(id);
 		};
 		img.src = url;
 	}
@@ -133,8 +133,8 @@
 		const url = URL.createObjectURL(file);
 		const pos = getSpawnPosition();
 
-		state.addAsset(assetId, { blob: file, url, filename: file.name });
-		state.addItem({
+		appState.addAsset(assetId, { blob: file, url, filename: file.name });
+		appState.addItem({
 			id,
 			assetId,
 			html: `<audio src="${url}" controls></audio>`,
@@ -146,9 +146,9 @@
 			width: 300,
 			height: 54,
 			rotation: 0,
-			zIndex: state.maxZIndex + 1
+			zIndex: appState.maxZIndex + 1
 		});
-		state.select(id);
+		appState.select(id);
 	}
 
 	function addVideoItem(file: File) {
@@ -159,8 +159,8 @@
 
 		const video = document.createElement('video');
 		video.onloadedmetadata = () => {
-			state.addAsset(assetId, { blob: file, url, filename: file.name });
-			state.addItem({
+			appState.addAsset(assetId, { blob: file, url, filename: file.name });
+			appState.addItem({
 				id,
 				assetId,
 				html: `<video src="${url}" controls></video>`,
@@ -173,9 +173,9 @@
 				width: video.videoWidth || 640,
 				height: video.videoHeight || 360,
 				rotation: 0,
-				zIndex: state.maxZIndex + 1
+				zIndex: appState.maxZIndex + 1
 			});
-			state.select(id);
+			appState.select(id);
 		};
 		video.src = url;
 	}
diff --git a/src/lib/io.ts b/src/lib/io.ts
index 8100ffc..883da8a 100644
--- a/src/lib/io.ts
+++ b/src/lib/io.ts
@@ -102,7 +102,7 @@ export async function importBoard(
 			}
 		}
 
-		state.load(manifest, assets);
+		await state.load(manifest, assets);
 		return { success: true };
 	} catch (e) {
 		return {
@@ -175,8 +175,7 @@ export async function mergeBoard(
 			};
 		});
 
-		state.addAssets(newAssets);
-		state.addItems(newItems);
+		await state.mergeData(newAssets, newItems);
 
 		return { success: true, itemCount: newItems.length };
 	} catch (e) {
diff --git a/src/lib/state.svelte.ts b/src/lib/state.svelte.ts
index fb57e58..7c23ff2 100644
--- a/src/lib/state.svelte.ts
+++ b/src/lib/state.svelte.ts
@@ -93,22 +93,30 @@ function createState() {
 			: 0,
 	);
 
-	async function save() {
+	async function saveNow(): Promise<void> {
+		if (saveTimeout) {
+			clearTimeout(saveTimeout);
+			saveTimeout = null;
+		}
+		const storedAssets: Record<string, StoredAsset> = {};
+		for (const [id, asset] of Object.entries(assets)) {
+			storedAssets[id] = {
+				dataUrl: await blobToDataUrl(asset.blob),
+				filename: asset.filename,
+			};
+		}
+		const stored: StoredState = { manifest, assets: storedAssets };
+		try {
+			localStorage.setItem(STORAGE_KEY, JSON.stringify(stored));
+		} catch {
+			// localStorage full or unavailable
+		}
+	}
+
+	function save() {
 		if (saveTimeout) clearTimeout(saveTimeout);
-		saveTimeout = setTimeout(async () => {
-			const storedAssets: Record<string, StoredAsset> = {};
-			for (const [id, asset] of Object.entries(assets)) {
-				storedAssets[id] = {
-					dataUrl: await blobToDataUrl(asset.blob),
-					filename: asset.filename,
-				};
-			}
-			const stored: StoredState = { manifest, assets: storedAssets };
-			try {
-				localStorage.setItem(STORAGE_KEY, JSON.stringify(stored));
-			} catch {
-				// localStorage full or unavailable
-			}
+		saveTimeout = setTimeout(() => {
+			saveNow();
 		}, 500);
 	}
 
@@ -181,6 +189,12 @@ function createState() {
 		save();
 	}
 
+	async function mergeData(newAssets: AssetStore, newItems: Item[]): Promise<void> {
+		Object.assign(assets, newAssets);
+		manifest.items.push(...newItems);
+		await saveNow();
+	}
+
 	function getItem(id: string): Item | undefined {
 		return manifest.items.find((i) => i.id === id);
 	}
@@ -417,8 +431,16 @@ function createState() {
 		localStorage.removeItem(STORAGE_KEY);
 	}
 
-	function load(newManifest: Manifest, newAssets: AssetStore) {
+	async function load(newManifest: Manifest, newAssets: AssetStore): Promise<void> {
 		Object.values(assets).forEach((a) => URL.revokeObjectURL(a.url));
+
+		for (const item of newManifest.items) {
+			if (item.assetId && newAssets[item.assetId]) {
+				const newUrl = newAssets[item.assetId].url;
+				item.html = item.html.replace(/src="[^"]*"/g, `src="${newUrl}"`);
+			}
+		}
+
 		manifest = newManifest;
 		assets = newAssets;
 		viewport = { x: 0, y: 0, zoom: 1 };
@@ -426,7 +448,7 @@ function createState() {
 		editingId = null;
 		editingGlobal = false;
 		focusedId = null;
-		save();
+		await saveNow();
 	}
 
 	restore();
@@ -468,6 +490,7 @@ function createState() {
 		removeItem,
 		addAsset,
 		addAssets,
+		mergeData,
 		getItem,
 		select,
 		toggleSelection,
diff --git a/vite.config.ts b/vite.config.ts
index 6f6eaa6..e5e6161 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -4,4 +4,7 @@ import { svelte } from '@sveltejs/vite-plugin-svelte';
 // https://vite.dev/config/
 export default defineConfig({
 	plugins: [svelte()],
+	build: {
+		chunkSizeWarningLimit: 1000,
+	},
 });