diff --git a/public/app.js b/public/app.js
new file mode 100644
index 0000000..74b98f5
--- /dev/null
+++ b/public/app.js
@@ -0,0 +1,576 @@
+const notification = document.getElementById('notification');
+const currentDateEl = document.getElementById('current-date');
+const orderDateInput = document.getElementById('order-date');
+const customerNameInput = document.getElementById('customer-name');
+const orderForm = document.getElementById('order-form');
+const ordersContainer = document.getElementById('orders');
+const inventoryList = document.getElementById('inventory');
+const advanceButton = document.getElementById('advance-date');
+
+const API_BASE =
+  window.location.protocol === 'file:' ? 'http://localhost:3000' : window.location.origin;
+
+let products = [];
+let orders = [];
+let currentDate = '';
+
+function getLocalISODate() {
+  const now = new Date();
+  const offsetMs = now.getTimezoneOffset() * 60 * 1000;
+  return new Date(now.getTime() - offsetMs).toISOString().slice(0, 10);
+}
+
+class OrderCard {
+  constructor(order, allOrders, allProducts) {
+    this.order = order;
+    this.orders = allOrders;
+    this.products = allProducts;
+  }
+
+  build() {
+    const card = document.createElement('div');
+    card.className = 'card shadow-sm order-card';
+
+    const body = document.createElement('div');
+    body.className = 'card-body';
+
+    body.appendChild(this.buildHeader());
+    body.appendChild(this.buildItemsSection());
+
+    card.appendChild(body);
+    return card;
+  }
+
+  buildHeader() {
+    const header = document.createElement('div');
+    header.className = 'd-flex justify-content-between flex-wrap gap-2';
+
+    const info = document.createElement('div');
+    const name = document.createElement('h3');
+    name.className = 'h5 mb-1';
+    name.textContent = this.order.customer_name;
+
+    const idMeta = document.createElement('div');
+    idMeta.className = 'text-muted order-meta';
+    idMeta.textContent = `ID: ${this.order.id}`;
+
+    const dateMeta = document.createElement('div');
+    dateMeta.className = 'text-muted order-meta';
+    dateMeta.textContent = `Дата: ${this.order.order_date}`;
+
+    info.appendChild(name);
+    info.appendChild(idMeta);
+    info.appendChild(dateMeta);
+
+    const actions = document.createElement('div');
+    actions.className = 'd-flex gap-2 align-items-start';
+    actions.appendChild(this.buildButton('Изменить', 'btn-outline-secondary', {
+      action: 'edit-order',
+      id: this.order.id
+    }));
+    actions.appendChild(this.buildButton('Удалить', 'btn-outline-danger', {
+      action: 'delete-order',
+      id: this.order.id
+    }));
+
+    header.appendChild(info);
+    header.appendChild(actions);
+
+    return header;
+  }
+
+  buildItemsSection() {
+    const wrapper = document.createElement('div');
+    wrapper.className = 'mt-3';
+
+    wrapper.appendChild(this.buildItemsTable());
+    wrapper.appendChild(this.buildAddItemForm());
+
+    return wrapper;
+  }
+
+  buildItemsTable() {
+    const table = document.createElement('table');
+    table.className = 'table table-sm align-middle';
+
+    table.innerHTML = `
+      <thead>
+        <tr>
+          <th>ID</th>
+          <th>Товар</th>
+          <th>Количество</th>
+          <th class="text-end">Действия</th>
+        </tr>
+      </thead>
+    `;
+
+    const body = document.createElement('tbody');
+    this.order.items.forEach((item) => {
+      body.appendChild(this.buildItemRow(item));
+    });
+
+    table.appendChild(body);
+    return table;
+  }
+
+  buildItemRow(item) {
+    const row = document.createElement('tr');
+
+    const idCell = document.createElement('td');
+    idCell.className = 'text-muted small';
+    idCell.textContent = item.product_id ?? item.id;
+
+    const productCell = document.createElement('td');
+    const productSelect = this.buildProductSelect(item);
+    productSelect.classList.add('form-select-sm');
+    productSelect.dataset.action = 'item-product';
+    productSelect.dataset.itemId = item.id;
+    productSelect.setAttribute('aria-label', 'Товар');
+    productCell.appendChild(productSelect);
+
+    const quantityCell = document.createElement('td');
+    const quantityInput = document.createElement('input');
+    quantityInput.type = 'number';
+    quantityInput.min = '1';
+    quantityInput.className = 'form-control form-control-sm';
+    quantityInput.value = item.quantity;
+    quantityInput.dataset.action = 'item-quantity';
+    quantityInput.dataset.itemId = item.id;
+    quantityInput.setAttribute('aria-label', 'Количество');
+    quantityCell.appendChild(quantityInput);
+
+    const actionsCell = document.createElement('td');
+    actionsCell.className = 'text-end item-actions';
+    actionsCell.appendChild(this.buildItemActionButtons(item));
+    actionsCell.appendChild(this.buildMoveControls(item));
+
+    row.appendChild(idCell);
+    row.appendChild(productCell);
+    row.appendChild(quantityCell);
+    row.appendChild(actionsCell);
+
+    return row;
+  }
+
+  buildItemActionButtons(item) {
+    const wrapper = document.createElement('div');
+    wrapper.className = 'd-flex gap-2 justify-content-end';
+
+    wrapper.appendChild(
+      this.buildButton('Сохранить', 'btn-outline-primary', {
+        action: 'save-item',
+        orderId: this.order.id,
+        itemId: item.id
+      })
+    );
+    wrapper.appendChild(
+      this.buildButton('Удалить', 'btn-outline-danger', {
+        action: 'delete-item',
+        orderId: this.order.id,
+        itemId: item.id
+      })
+    );
+
+    return wrapper;
+  }
+
+  buildMoveControls(item) {
+    const wrapper = document.createElement('div');
+    wrapper.className = 'd-flex gap-2 justify-content-end mt-2';
+
+    const select = document.createElement('select');
+    select.className = 'form-select form-select-sm';
+    select.dataset.action = 'move-target';
+    select.dataset.itemId = item.id;
+    select.setAttribute('aria-label', 'Выбор заказа для перемещения');
+
+    const placeholder = document.createElement('option');
+    placeholder.value = '';
+    placeholder.textContent = 'Переместить в...';
+    select.appendChild(placeholder);
+
+    this.orders
+      .filter((otherOrder) => otherOrder.id !== this.order.id)
+      .forEach((otherOrder) => {
+        const option = document.createElement('option');
+        option.value = otherOrder.id;
+        option.textContent = otherOrder.customer_name;
+        select.appendChild(option);
+      });
+
+    wrapper.appendChild(select);
+    wrapper.appendChild(
+      this.buildButton('Перенести', 'btn-outline-secondary', {
+        action: 'move-item',
+        itemId: item.id
+      })
+    );
+
+    return wrapper;
+  }
+
+  buildAddItemForm() {
+    const form = document.createElement('form');
+    form.className = 'row g-2 align-items-end';
+    form.dataset.action = 'add-item';
+    form.dataset.orderId = this.order.id;
+
+    const productCol = document.createElement('div');
+    productCol.className = 'col-md-6';
+    const productLabel = document.createElement('label');
+    productLabel.className = 'form-label';
+    productLabel.textContent = 'Товар';
+    const productSelect = this.buildProductSelect();
+    const productSelectId = `add-item-product-${this.order.id}`;
+    productSelect.name = 'productId';
+    productSelect.id = productSelectId;
+    productLabel.htmlFor = productSelectId;
+    productCol.appendChild(productLabel);
+    productCol.appendChild(productSelect);
+
+    const quantityCol = document.createElement('div');
+    quantityCol.className = 'col-md-3';
+    const quantityLabel = document.createElement('label');
+    quantityLabel.className = 'form-label';
+    quantityLabel.textContent = 'Кол-во';
+    const quantityInput = document.createElement('input');
+    const quantityInputId = `add-item-quantity-${this.order.id}`;
+    quantityInput.type = 'number';
+    quantityInput.min = '1';
+    quantityInput.className = 'form-control';
+    quantityInput.name = 'quantity';
+    quantityInput.id = quantityInputId;
+    quantityLabel.htmlFor = quantityInputId;
+    quantityInput.required = true;
+    quantityCol.appendChild(quantityLabel);
+    quantityCol.appendChild(quantityInput);
+
+    const actionCol = document.createElement('div');
+    actionCol.className = 'col-md-3';
+    const addButton = document.createElement('button');
+    addButton.type = 'submit';
+    addButton.className = 'btn btn-success w-100';
+    addButton.textContent = 'Добавить позицию';
+    actionCol.appendChild(addButton);
+
+    form.appendChild(productCol);
+    form.appendChild(quantityCol);
+    form.appendChild(actionCol);
+
+    return form;
+  }
+
+  buildProductSelect(selectedId) {
+    const select = document.createElement('select');
+    select.className = 'form-select';
+    this.products.forEach((product) => {
+      const option = document.createElement('option');
+      option.value = product.id;
+      option.textContent = product.name;
+      if (selectedId && product.id === selectedId) {
+        option.selected = true;
+      }
+      select.appendChild(option);
+    });
+    return select;
+  }
+
+  buildButton(label, style, data = {}) {
+    const button = document.createElement('button');
+    button.type = 'button';
+    button.className = `btn ${style} btn-sm`;
+    button.textContent = label;
+    Object.entries(data).forEach(([key, value]) => {
+      button.dataset[key] = value;
+    });
+    return button;
+  }
+}
+
+function showNotification(message, type = 'warning') {
+  notification.textContent = message;
+  notification.className = `alert alert-${type}`;
+  notification.classList.remove('d-none');
+
+  setTimeout(() => {
+    notification.classList.add('d-none');
+  }, 4000);
+}
+
+function resolveApiUrl(url) {
+  if (url.startsWith('http://') || url.startsWith('https://')) {
+    return url;
+  }
+  if (url.startsWith('/')) {
+    return `${API_BASE}${url}`;
+  }
+  return `${API_BASE}/${url}`;
+}
+
+async function fetchJson(url, options) {
+  const response = await fetch(resolveApiUrl(url), options);
+  if (!response.ok) {
+    const payload = await response.json().catch(() => ({ message: 'Ошибка запроса.' }));
+    throw new Error(payload.message || 'Ошибка запроса.');
+  }
+  if (response.status === 204) {
+    return null;
+  }
+  return response.json();
+}
+
+function renderInventory() {
+  inventoryList.innerHTML = '';
+  products.forEach((product) => {
+    const item = document.createElement('li');
+    item.className = 'list-group-item d-flex justify-content-between align-items-center';
+    item.innerHTML = `
+      <span>${product.name}</span>
+      <span class="badge bg-secondary rounded-pill">${product.quantity}</span>
+    `;
+    inventoryList.appendChild(item);
+  });
+}
+
+function renderOrders() {
+  ordersContainer.innerHTML = '';
+  if (orders.length === 0) {
+    ordersContainer.innerHTML = '<p class="text-muted">Заказы отсутствуют.</p>';
+    return;
+  }
+
+  orders.forEach((order) => {
+    const card = new OrderCard(order, orders, products).build();
+    ordersContainer.appendChild(card);
+  });
+}
+
+function normalizeProducts(data) {
+  if (!Array.isArray(data)) {
+    return [];
+  }
+  return data.map((product) => ({
+    id: product.id ?? product.ID,
+    name: product.name ?? product.pr_name,
+    quantity: product.quantity ?? product.count
+  }));
+}
+
+function normalizeOrderItems(items) {
+  if (!Array.isArray(items)) {
+    return [];
+  }
+  return items.map((item, index) => ({
+    id: item.id ?? item.item_id ?? `${item.product_id ?? item.productId ?? 'item'}-${index}`,
+    product_id: item.product_id ?? item.productId ?? item.product,
+    product_name: item.product_name ?? item.name,
+    quantity: item.quantity,
+    price: item.price
+  }));
+}
+
+function normalizeOrders(data) {
+  if (!Array.isArray(data)) {
+    return [];
+  }
+  return data.map((order) => ({
+    id: order.id ?? order.ID,
+    customer_name: order.customer_name ?? order.customer,
+    order_date: order.order_date ?? order.date,
+    status: order.status,
+    total_amount: order.total_amount ?? order.total,
+    items: normalizeOrderItems(order.items)
+  }));
+}
+
+async function refreshData() {
+  const [currentDateData, productsData, ordersData] = await Promise.all([
+    fetchJson('/api/current-date'),
+    fetchJson('/api/products'),
+    fetchJson('/api/orders')
+  ]);
+  currentDate = currentDateData.currentDate;
+  products = normalizeProducts(productsData);
+  orders = normalizeOrders(ordersData);
+
+  currentDateEl.textContent = currentDate;
+  orderDateInput.min = currentDate;
+  if (!orderDateInput.value) {
+    orderDateInput.value = currentDate;
+  }
+
+  renderInventory();
+  renderOrders();
+}
+
+function initializeApp() {
+  const requiredElements = [
+    notification,
+    currentDateEl,
+    orderDateInput,
+    customerNameInput,
+    orderForm,
+    ordersContainer,
+    inventoryList,
+    advanceButton
+  ];
+
+  if (requiredElements.some((element) => !element)) {
+    console.error('Missing required elements. Проверьте разметку страницы.');
+    return;
+  }
+
+  const initialDate = getLocalISODate();
+  currentDate = initialDate;
+  currentDateEl.textContent = initialDate;
+  orderDateInput.min = initialDate;
+  if (!orderDateInput.value) {
+    orderDateInput.value = initialDate;
+  }
+
+  orderForm.addEventListener('submit', async (event) => {
+    event.preventDefault();
+    try {
+      await fetchJson('/api/orders', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          customerName: customerNameInput.value.trim(),
+          orderDate: orderDateInput.value
+        })
+      });
+      customerNameInput.value = '';
+      orderDateInput.value = currentDate;
+      await refreshData();
+    } catch (error) {
+      showNotification(error.message, 'warning');
+    }
+  });
+
+  advanceButton.addEventListener('click', async () => {
+    try {
+      await fetchJson('/api/current-date/advance', { method: 'POST' });
+      await refreshData();
+      showNotification('Дата переведена. Заказы за сегодня отправлены.', 'success');
+    } catch (error) {
+      showNotification(error.message, 'warning');
+    }
+  });
+
+  ordersContainer.addEventListener('submit', async (event) => {
+    if (event.target.matches('form[data-action="add-item"]')) {
+      event.preventDefault();
+      const orderId = event.target.dataset.orderId;
+      const productId = event.target.productId.value;
+      const quantity = Number.parseInt(event.target.quantity.value, 10);
+
+      try {
+        const response = await fetchJson(`/api/orders/${orderId}/items`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ productId, quantity })
+        });
+        const order = orders.find((entry) => entry.id === orderId);
+        const product = products.find((entry) => entry.id === productId);
+        if (order) {
+          const newItem = normalizeOrderItems([
+            {
+              id: response?.itemId,
+              product_id: productId,
+              product_name: product?.name,
+              quantity
+            }
+          ])[0];
+          order.items = [...order.items, newItem];
+          renderOrders();
+        }
+        event.target.reset();
+        await refreshData();
+      } catch (error) {
+        showNotification(error.message, 'warning');
+      }
+    }
+  });
+
+  ordersContainer.addEventListener('click', async (event) => {
+    const { action, id, itemId, orderId } = event.target.dataset;
+
+    try {
+      if (action === 'delete-order') {
+        await fetchJson(`/api/orders/${id}`, { method: 'DELETE' });
+        await refreshData();
+        return;
+      }
+
+      if (action === 'edit-order') {
+        const newName = prompt('Введите новое ФИО заказчика', '');
+        if (newName === null) {
+          return;
+        }
+        const newDate = prompt('Введите дату заказа (YYYY-MM-DD)', currentDate);
+        if (!newDate) {
+          return;
+        }
+        Date
+        await fetchJson(`/api/orders/${id}`, {
+          method: 'PUT',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ customerName: newName, orderDate: newDate })
+        });
+        await refreshData();
+        return;
+      }
+
+      if (action === 'save-item') {
+        const quantityInput = ordersContainer.querySelector(
+          `[data-action="item-quantity"][data-item-id="${itemId}"]`
+        );
+        const productSelect = ordersContainer.querySelector(
+          `[data-action="item-product"][data-item-id="${itemId}"]`
+        );
+
+        await fetchJson(`/api/orders/${orderId}/items/${itemId}`, {
+          method: 'PUT',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({
+            productId: productSelect.value,
+            quantity: Number.parseInt(quantityInput.value, 10)
+          })
+        });
+        await refreshData();
+        return;
+      }
+
+      if (action === 'delete-item') {
+        await fetchJson(`/api/orders/${orderId}/items/${itemId}`, { method: 'DELETE' });
+        await refreshData();
+        return;
+      }
+
+      if (action === 'move-item') {
+        const targetSelect = ordersContainer.querySelector(
+          `[data-action="move-target"][data-item-id="${itemId}"]`
+        );
+        if (!targetSelect.value) {
+          showNotification('Выберите заказ для перемещения.', 'warning');
+          return;
+        }
+        await fetchJson(`/api/order-items/${itemId}/move`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ targetOrderId: targetSelect.value })
+        });
+        await refreshData();
+        return;
+      }
+    } catch (error) {
+      showNotification(error.message, 'warning');
+    }
+  });
+
+  refreshData().catch((error) => {
+    showNotification(error.message, 'warning');
+  });
+}
+
+initializeApp();
\ No newline at end of file