diff --git a/src/components/BookingModal.astro b/src/components/BookingModal.astro
index 6fb3994..ad47e49 100644
--- a/src/components/BookingModal.astro
+++ b/src/components/BookingModal.astro
@@ -44,6 +44,7 @@
 
 <script>
     import { seatLayouts, occupiedSeatsData, prices, cart, updateCart } from "../scripts/bigConstants";
+    import type { MovieCartItem } from "../scripts/bigConstants";
 
     let currentBookingContext: any = null;
     let currentHallLayout: any = null;
@@ -120,15 +121,16 @@
         const selected = Array.from(document.querySelectorAll("#seat-grid .seat.selected")) as HTMLElement[];
         if (!selected.length) return alert("Bitte wähle Plätze aus.");
         selected.forEach(seat => {
-            cart.push({
+            const ticket: MovieCartItem = {
                 id: Date.now() + Math.random(),
                 category: "movie",
                 title: currentBookingContext.movie,
                 hall: currentBookingContext.hall,
                 time: currentBookingContext.time,
-                seatId: seat.dataset.seatId,
-                price: prices[seat.dataset.type as keyof typeof prices] || prices.normal
-            });
+                seatId: seat.dataset.seatId ?? "",
+                price: prices[seat.dataset.type as keyof typeof prices] ?? prices.normal
+            };
+            cart.push(ticket);
         });
         updateCart(cart);
         window.dispatchEvent(new CustomEvent("cart-updated"));
diff --git a/src/components/CartView.astro b/src/components/CartView.astro
index afd84f5..2ea97cc 100644
--- a/src/components/CartView.astro
+++ b/src/components/CartView.astro
@@ -38,13 +38,14 @@
 
 <script>
     import { cart, updateCart } from "../scripts/bigConstants";
+    import type { CartItem, MovieCartItem, SnackCartItem } from "../scripts/bigConstants";
 
     function formatEuro(value: number) {
         return `${Number(value || 0).toFixed(2).replace(".", ",")} EUR`;
     }
 
-    function escapeHtml(value: any) {
-        return String(value || "")
+    function escapeHtml(value: string | number | undefined | null) {
+        return String(value ?? "")
             .replaceAll("&", "&amp;")
             .replaceAll("<", "&lt;")
             .replaceAll(">", "&gt;")
@@ -52,52 +53,60 @@
             .replaceAll("'", "&#39;");
     }
 
-    function buildCartKey(item: any) {
+    function buildCartKey(item: CartItem) {
         const infoText = item.category === "movie"
-            ? `Sitz: ${item.seatId} (${item.hall})`
+            ? `Sitz: ${(item as MovieCartItem).seatId} (${item.hall})`
             : item.time;
         return `${item.title}-${item.hall}-${infoText}`;
     }
 
-    function isDrinkItem(item: any) {
+    function isDrinkItem(item: CartItem): item is SnackCartItem {
         if (item.category !== "snack") return false;
-        const title = String(item.title || "").toLowerCase();
-        const size = String(item.hall || "").toLowerCase();
+        const title = item.title.toLowerCase();
+        const size = item.hall.toLowerCase();
         const drinkKeywords = ["cola", "sprite", "fanta", "mezzo", "fuze", "wasser", "getraenk", "drink"];
         return drinkKeywords.some((word) => title.includes(word)) || size.includes("l");
     }
 
-    function buildItemInfo(item: any) {
+    function buildItemInfo(item: CartItem) {
         if (item.category === "movie") {
+            const movie = item as MovieCartItem;
             return `
-                <div>Sitzplatz: ${escapeHtml(item.seatId || "-")}</div>
-                <div>Saal: ${escapeHtml(item.hall || "-")}</div>
-                <div>Uhrzeit: ${escapeHtml(item.time || "-")} Uhr</div>
+                <div>Sitzplatz: ${escapeHtml(movie.seatId)}</div>
+                <div>Saal: ${escapeHtml(movie.hall)}</div>
+                <div>Uhrzeit: ${escapeHtml(movie.time)} Uhr</div>
             `;
         }
         if (isDrinkItem(item)) {
             return `
-                <div>Variante: ${escapeHtml(item.time || "-")}</div>
-                <div>Groesse: ${escapeHtml(item.hall || "-")}</div>
+                <div>Variante: ${escapeHtml(item.time)}</div>
+                <div>Groesse: ${escapeHtml(item.hall)}</div>
             `;
         }
         return `
             <div>Kategorie: Snack</div>
-            <div>Variante: ${escapeHtml(item.time || "-")}</div>
-            <div>Groesse: ${escapeHtml(item.hall || "-")}</div>
+            <div>Variante: ${escapeHtml(item.time)}</div>
+            <div>Groesse: ${escapeHtml(item.hall)}</div>
         `;
     }
 
-    function groupCartItems() {
-        const groups = new Map();
-        cart.forEach((item: any) => {
+    interface CartGroup {
+        key: string;
+        quantity: number;
+        total: number;
+        item: CartItem;
+    }
+
+    function groupCartItems(): CartGroup[] {
+        const groups = new Map<string, CartGroup>();
+        cart.forEach((item: CartItem) => {
             const key = buildCartKey(item);
             if (!groups.has(key)) {
                 groups.set(key, { key, quantity: 0, total: 0, item });
             }
-            const group = groups.get(key);
+            const group = groups.get(key)!;
             group.quantity += 1;
-            group.total += Number(item.price || 0);
+            group.total += item.price;
         });
         return Array.from(groups.values());
     }
@@ -128,7 +137,7 @@
             </div>
         `;
 
-        const rows = groupedItems.map((group) => {
+        const rows = groupedItems.map((group: CartGroup) => {
             const imageHtml = group.item.img
                 ? `<img class="cart-img-small" src="${escapeHtml(group.item.img)}" alt="${escapeHtml(group.item.title)}">`
                 : `<div class="cart-img-fallback">Kein Bild</div>`;
@@ -158,7 +167,7 @@
 
         cartList.innerHTML = header + rows;
 
-        const total = cart.reduce((sum, item) => sum + Number(item.price || 0), 0);
+        const total = cart.reduce((sum: number, item: CartItem) => sum + item.price, 0);
         const vat = total - total / 1.19;
         totalEl.innerText = formatEuro(total);
         vatEl.innerText = `inkl. 19% MwSt: ${formatEuro(vat)}`;
@@ -167,25 +176,26 @@
     window.addEventListener("cart-updated", renderCart);
     renderCart();
 
-    document.getElementById("cart-view")?.addEventListener("click", (event: any) => {
-        const deleteBtn = event.target.closest(".btn-delete-item");
+    document.getElementById("cart-view")?.addEventListener("click", (event: Event) => {
+        const target = event.target as HTMLElement;
+        const deleteBtn = target.closest(".btn-delete-item") as HTMLElement | null;
         if (deleteBtn) {
             const key = deleteBtn.dataset.key;
-            const newCart = cart.filter(item => buildCartKey(item) !== key);
+            const newCart = cart.filter((item: CartItem) => buildCartKey(item) !== key);
             updateCart(newCart);
             window.dispatchEvent(new CustomEvent("cart-updated"));
             return;
         }
 
-        const qtyBtn = event.target.closest(".btn-qty");
+        const qtyBtn = target.closest(".btn-qty") as HTMLElement | null;
         if (qtyBtn) {
             const action = qtyBtn.dataset.action;
             const key = qtyBtn.dataset.key;
             if (action === "plus") {
-                const item = cart.find(i => buildCartKey(i) === key);
-                if (item) cart.push({...item, id: Date.now() + Math.random()});
+                const item = cart.find((i: CartItem) => buildCartKey(i) === key);
+                if (item) cart.push({ ...item, id: Date.now() + Math.random() });
             } else {
-                const idx = cart.findIndex(i => buildCartKey(i) === key);
+                const idx = cart.findIndex((i: CartItem) => buildCartKey(i) === key);
                 if (idx !== -1) cart.splice(idx, 1);
             }
             updateCart(cart);
diff --git a/src/components/CheckoutView.astro b/src/components/CheckoutView.astro
index 13cac92..c2a37ee 100644
--- a/src/components/CheckoutView.astro
+++ b/src/components/CheckoutView.astro
@@ -53,6 +53,7 @@
 
 <script>
     import { currentUser, users, cart, emptyCart, occupiedSeatsData, updateCart, updateOccupiedSeats } from "../scripts/bigConstants";
+    import type { CartItem, MovieCartItem } from "../scripts/bigConstants";
 
     function formatCheckoutEuro(value: number) {
         return `${Number(value || 0).toFixed(2).replace(".", ",")} EUR`;
@@ -90,15 +91,15 @@
         if (!summaryList) return;
         summaryList.innerHTML = "";
 
-        const total = cart.reduce((sum: number, item: any) => sum + Number(item.price || 0), 0);
+        const total = cart.reduce((sum: number, item: CartItem) => sum + item.price, 0);
         const vat = total - total / 1.19;
 
-        cart.forEach((item: any) => {
+        cart.forEach((item: CartItem) => {
             const row = document.createElement("div");
             row.style.cssText = "display:flex; justify-content:space-between; gap:12px; margin-bottom:10px; font-size:0.95rem;";
             const infoText = item.category === "movie"
-                ? `Sitz ${item.seatId || "-"} | ${item.hall || "-"} | ${item.time || "-"} Uhr`
-                : `${item.time || "Standard"} | ${item.hall || "-"}`;
+                ? `Sitz ${(item as MovieCartItem).seatId} | ${item.hall} | ${item.time} Uhr`
+                : `${item.time || "Standard"} | ${item.hall}`;
             row.innerHTML = `<span>${item.title} (${infoText})</span><span>${formatCheckoutEuro(item.price)}</span>`;
             summaryList.appendChild(row);
         });
@@ -116,16 +117,16 @@
         const ticketContainer = document.getElementById("ticket-container");
         if (!ticketContainer) return;
 
-        const moviesInCart = cart.filter((item: any) => item.category === "movie");
+        const moviesInCart = cart.filter((item: CartItem): item is MovieCartItem => item.category === "movie");
         if (!moviesInCart.length) {
             ticketContainer.innerHTML = "<p>Danke für deinen Einkauf!</p>";
             return;
         }
 
-        const mainMovie = moviesInCart[0];
+        const mainMovie: MovieCartItem = moviesInCart[0];
         const matchingMovieSeats = moviesInCart
-            .filter((item: any) => item.title === mainMovie.title && item.time === mainMovie.time)
-            .map((item: any) => item.seatId)
+            .filter((item: MovieCartItem) => item.title === mainMovie.title && item.time === mainMovie.time)
+            .map((item: MovieCartItem) => item.seatId)
             .join(", ");
 
         const qrData = encodeURIComponent(`EAGLE-IMAX|${mainMovie.title}|${mainMovie.hall}|${matchingMovieSeats}`);
@@ -154,12 +155,11 @@
     }
 
     function completeCheckout() {
-        const orderItems = [...cart];
-        const orderTotal = orderItems.reduce((sum, item) => sum + Number(item.price || 0), 0);
+        const orderItems: CartItem[] = [...cart];
+        const orderTotal = orderItems.reduce((sum: number, item: CartItem) => sum + item.price, 0);
 
-        // Save order for current user
         if (currentUser && Array.isArray(users)) {
-            const userIndex = users.findIndex((entry: any) => entry.email === currentUser.email);
+            const userIndex = users.findIndex((entry: any) => entry.email === (currentUser as any).email);
             if (userIndex !== -1) {
                 if (!Array.isArray(users[userIndex].orders)) users[userIndex].orders = [];
                 users[userIndex].orders.push({
@@ -172,12 +172,13 @@
             }
         }
 
-        // Reserve seats
-        orderItems.filter(item => item.category === "movie").forEach(item => {
-            const key = `${item.hall}-${item.time}`;
-            if (!occupiedSeatsData[key]) occupiedSeatsData[key] = [];
-            occupiedSeatsData[key].push(item.seatId);
-        });
+        orderItems
+            .filter((item: CartItem): item is MovieCartItem => item.category === "movie")
+            .forEach((item: MovieCartItem) => {
+                const key = `${item.hall}-${item.time}`;
+                if (!occupiedSeatsData[key]) occupiedSeatsData[key] = [];
+                occupiedSeatsData[key].push(item.seatId);
+            });
         updateOccupiedSeats(occupiedSeatsData);
 
         emptyCart();
diff --git a/src/components/SnacksView.astro b/src/components/SnacksView.astro
index d52a0d5..1a9da22 100644
--- a/src/components/SnacksView.astro
+++ b/src/components/SnacksView.astro
@@ -450,6 +450,7 @@
 
 <script>
     import { cart, updateCart } from "../scripts/bigConstants";
+    import type { SnackCartItem } from "../scripts/bigConstants";
 
     const snacksView = document.getElementById("snacks-view");
 
@@ -471,7 +472,7 @@
         const activeOption = snackCard.querySelector(".opt-btn.active") as HTMLElement;
         const variantVal = activeOption ? activeOption.innerText : "Normal";
 
-        cart.push({
+        const snackItem: SnackCartItem = {
             id: Date.now() + Math.random(),
             category: "snack",
             title: snackTitle,
@@ -480,7 +481,8 @@
             type: "SNACK",
             price: priceVal,
             img: snackImg
-        });
+        };
+        cart.push(snackItem);
 
         updateCart(cart);
         window.dispatchEvent(new CustomEvent("cart-updated"));
diff --git a/src/scripts/bigConstants.ts b/src/scripts/bigConstants.ts
index c40e139..90bde8c 100644
--- a/src/scripts/bigConstants.ts
+++ b/src/scripts/bigConstants.ts
@@ -27,12 +27,12 @@ export const timePatterns = [
 export const weekdayShort = ["So", "Mo", "Di", "Mi", "Do", "Fr", "Sa"];
 
 // Shared State
-export const cart: unknown[] = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("eagleCart") || '[]') : '[]');
+export const cart: CartItem[] = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("eagleCart") || '[]') : '[]');
 export let occupiedSeatsData = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("eagleOccupied") || '{}') : '{}');
-export const users: unknown[] = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("eagleUsers") || '[]') : '[]');
-export let currentUser: unknown = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("currentUser") || 'null') : 'null');
+export const users: User[] = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("eagleUsers") || '[]') : '[]');
+export let currentUser: User | null = JSON.parse(typeof window !== 'undefined' ? (localStorage.getItem("currentUser") || 'null') : 'null');
 
-export function updateCart(newCart: unknown[]) {
+export function updateCart(newCart: CartItem[]) {
     cart.splice(0, cart.length, ...newCart);
     if (typeof window !== 'undefined') {
         localStorage.setItem("eagleCart", JSON.stringify(cart));
@@ -57,7 +57,7 @@ export function persistUsers() {
     if (typeof window !== 'undefined') localStorage.setItem("eagleUsers", JSON.stringify(users));
 }
 
-export function persistCurrentUser(user: unknown) {
+export function persistCurrentUser(user: User | null) {
     currentUser = user;
     if (typeof window !== 'undefined') {
         if (currentUser) localStorage.setItem("currentUser", JSON.stringify(currentUser));
@@ -65,6 +65,30 @@ export function persistCurrentUser(user: unknown) {
     }
 }
 
+export interface BaseCartItem {
+    id: number;
+    category: "movie" | "snack";
+    title: string;
+    /** Hall name for movies; size label (e.g. "0,33L") for snacks */
+    hall: string;
+    /** Showtime for movies; flavour/variant for snacks */
+    time: string;
+    price: number;
+    img?: string;
+}
+
+export interface MovieCartItem extends BaseCartItem {
+    category: "movie";
+    seatId: string;
+}
+
+export interface SnackCartItem extends BaseCartItem {
+    category: "snack";
+    type: "SNACK";
+}
+
+export type CartItem = MovieCartItem | SnackCartItem;
+
 export interface User {
     firstName: string;
     lastName: string;