diff --git a/src/admin/components/OrderConfirmationModal.tsx b/src/admin/components/OrderConfirmationModal.tsx
index 3cb2570..1a13eac 100644
--- a/src/admin/components/OrderConfirmationModal.tsx
+++ b/src/admin/components/OrderConfirmationModal.tsx
@@ -7,7 +7,22 @@ import { useTheme } from "@mui/material/styles";
 import { Modal, Button, TextField, Field } from "../ui";
 import { useAlert } from "../context/AlertContext";
 
+// Editable line-item. quantity/unit_price/vat_rate are held as the raw typed
+// string while editing (so a field can be cleared — empty renders fine in a
+// type="number" input) and are coerced to numbers in handleEditGenerate before
+// being handed to onGenerate (the parent posts them verbatim).
 interface ConfirmationItem {
+  description: string;
+  quantity: string | number;
+  unit: string;
+  unit_price: string | number;
+  is_included_in_total: boolean;
+  vat_rate: string | number;
+}
+
+// Numeric shape handed to the parent (the raw editing strings are coerced in
+// handleEditGenerate). Distinct from the editable ConfirmationItem.
+interface GeneratedItem {
   description: string;
   quantity: number;
   unit: string;
@@ -22,7 +37,7 @@ interface OrderConfirmationModalProps {
   onGenerate: (
     lang: string,
     applyVat: boolean,
-    items?: ConfirmationItem[],
+    items?: GeneratedItem[],
   ) => Promise<void>;
   initialItems: ConfirmationItem[];
   orderNumber: string;
@@ -81,7 +96,17 @@ export default function OrderConfirmationModal({
   const handleEditGenerate = async () => {
     setLoading(true);
     try {
-      await onGenerate(lang, applyVatState, items);
+      // Coerce the raw typed strings back to numbers so an empty/partial field
+      // never reaches the server as NaN (the parent posts these verbatim).
+      const coercedItems: GeneratedItem[] = items.map((it) => ({
+        description: it.description,
+        quantity: Number(it.quantity) || 0,
+        unit: it.unit,
+        unit_price: Number(it.unit_price) || 0,
+        is_included_in_total: it.is_included_in_total,
+        vat_rate: Number(it.vat_rate) || 0,
+      }));
+      await onGenerate(lang, applyVatState, coercedItems);
       // Only close on success — on error keep the user's edited items intact.
       onClose();
     } catch (err) {
@@ -273,9 +298,9 @@ export default function OrderConfirmationModal({
                     <TextField
                       label="Množství"
                       type="number"
-                      value={item.quantity}
+                      value={item.quantity ?? ""}
                       onChange={(e) =>
-                        updateItem(i, "quantity", Number(e.target.value) || 0)
+                        updateItem(i, "quantity", e.target.value)
                       }
                       slotProps={{ htmlInput: { step: "0.001" } }}
                     />
@@ -287,18 +312,18 @@ export default function OrderConfirmationModal({
                     <TextField
                       label="Cena"
                       type="number"
-                      value={item.unit_price}
+                      value={item.unit_price ?? ""}
                       onChange={(e) =>
-                        updateItem(i, "unit_price", Number(e.target.value) || 0)
+                        updateItem(i, "unit_price", e.target.value)
                       }
                       slotProps={{ htmlInput: { step: "0.01" } }}
                     />
                     <TextField
                       label="%DPH"
                       type="number"
-                      value={item.vat_rate}
+                      value={item.vat_rate ?? ""}
                       onChange={(e) =>
-                        updateItem(i, "vat_rate", Number(e.target.value) || 0)
+                        updateItem(i, "vat_rate", e.target.value)
                       }
                       slotProps={{ htmlInput: { step: "1" } }}
                     />
@@ -350,15 +375,11 @@ export default function OrderConfirmationModal({
                       <td>
                         <TextField
                           type="number"
-                          value={item.quantity}
+                          value={item.quantity ?? ""}
                           onChange={(e) =>
-                            updateItem(
-                              i,
-                              "quantity",
-                              Number(e.target.value) || 0,
-                            )
+                            updateItem(i, "quantity", e.target.value)
                           }
-                          sx={{ width: 90 }}
+                          sx={{ width: 112 }}
                           slotProps={{ htmlInput: { step: "0.001" } }}
                         />
                       </td>
@@ -374,13 +395,9 @@ export default function OrderConfirmationModal({
                       <td>
                         <TextField
                           type="number"
-                          value={item.unit_price}
+                          value={item.unit_price ?? ""}
                           onChange={(e) =>
-                            updateItem(
-                              i,
-                              "unit_price",
-                              Number(e.target.value) || 0,
-                            )
+                            updateItem(i, "unit_price", e.target.value)
                           }
                           sx={{ width: 110 }}
                           slotProps={{ htmlInput: { step: "0.01" } }}
@@ -389,13 +406,9 @@ export default function OrderConfirmationModal({
                       <td>
                         <TextField
                           type="number"
-                          value={item.vat_rate}
+                          value={item.vat_rate ?? ""}
                           onChange={(e) =>
-                            updateItem(
-                              i,
-                              "vat_rate",
-                              Number(e.target.value) || 0,
-                            )
+                            updateItem(i, "vat_rate", e.target.value)
                           }
                           sx={{ width: 80 }}
                           slotProps={{ htmlInput: { step: "1" } }}
diff --git a/src/admin/pages/InvoiceDetail.tsx b/src/admin/pages/InvoiceDetail.tsx
index 24b2e5b..e30c5b8 100644
--- a/src/admin/pages/InvoiceDetail.tsx
+++ b/src/admin/pages/InvoiceDetail.tsx
@@ -166,9 +166,13 @@ interface InvoiceItem {
   _key: string;
   description: string;
   item_description: string;
-  quantity: number;
+  // Held as the raw typed string while editing so the field can be cleared
+  // (empty renders fine in a type="number" input). Coerced via Number(x) || 0
+  // only where used (live totals + save payload). vat_rate stays numeric: it
+  // is edited via a Select, never a free-text number input.
+  quantity: string | number;
   unit: string;
-  unit_price: number;
+  unit_price: string | number;
   vat_rate: number;
 }
 
@@ -332,10 +336,8 @@ function SortableInvoiceRow({
           <TextField
             label="Množství"
             type="number"
-            value={item.quantity}
-            onChange={(e) =>
-              onUpdate(index, "quantity", Number(e.target.value))
-            }
+            value={item.quantity ?? ""}
+            onChange={(e) => onUpdate(index, "quantity", e.target.value)}
             slotProps={{ htmlInput: { min: "0", step: "any" } }}
           />
           <TextField
@@ -347,10 +349,8 @@ function SortableInvoiceRow({
           <TextField
             label="Jedn. cena"
             type="number"
-            value={item.unit_price}
-            onChange={(e) =>
-              onUpdate(index, "unit_price", Number(e.target.value))
-            }
+            value={item.unit_price ?? ""}
+            onChange={(e) => onUpdate(index, "unit_price", e.target.value)}
             slotProps={{ htmlInput: { step: "any" } }}
           />
           {apply_vat && (
@@ -438,8 +438,8 @@ function SortableInvoiceRow({
       <TableCell>
         <TextField
           type="number"
-          value={item.quantity}
-          onChange={(e) => onUpdate(index, "quantity", Number(e.target.value))}
+          value={item.quantity ?? ""}
+          onChange={(e) => onUpdate(index, "quantity", e.target.value)}
           slotProps={{ htmlInput: { min: "0", step: "any" } }}
           sx={{ "& input": { textAlign: "center" } }}
         />
@@ -455,10 +455,8 @@ function SortableInvoiceRow({
       <TableCell>
         <TextField
           type="number"
-          value={item.unit_price}
-          onChange={(e) =>
-            onUpdate(index, "unit_price", Number(e.target.value))
-          }
+          value={item.unit_price ?? ""}
+          onChange={(e) => onUpdate(index, "unit_price", e.target.value)}
           slotProps={{ htmlInput: { step: "any" } }}
           sx={{ "& input": { textAlign: "right" } }}
         />
@@ -1036,6 +1034,10 @@ export default function InvoiceDetail() {
           .filter((i) => i.description.trim())
           .map((item, i) => ({
             ...item,
+            // Coerce the raw typed strings back to numbers so an empty/partial
+            // field never reaches the server as NaN (mirrors createTotals).
+            quantity: Number(item.quantity) || 0,
+            unit_price: Number(item.unit_price) || 0,
             position: i,
           })),
       };
@@ -2065,7 +2067,7 @@ export default function InvoiceDetail() {
                           #
                         </TableCell>
                         <TableCell>Popis</TableCell>
-                        <TableCell sx={{ width: "5.5rem" }} align="center">
+                        <TableCell sx={{ width: "7rem" }} align="center">
                           Množství
                         </TableCell>
                         <TableCell sx={{ width: "5.5rem" }} align="center">
diff --git a/src/admin/pages/IssuedOrderDetail.tsx b/src/admin/pages/IssuedOrderDetail.tsx
index 03fbea7..f75e967 100644
--- a/src/admin/pages/IssuedOrderDetail.tsx
+++ b/src/admin/pages/IssuedOrderDetail.tsx
@@ -141,9 +141,13 @@ interface OrderItem {
   _key: string;
   description: string;
   item_description: string;
-  quantity: number;
+  // Held as the raw typed string while editing so the field can be cleared
+  // (empty renders fine in a type="number" input). Coerced via Number(x) || 0
+  // only where used (live totals + save payload). vat_rate stays numeric: it
+  // is edited via a Select, never a free-text number input.
+  quantity: string | number;
   unit: string;
-  unit_price: number;
+  unit_price: string | number;
   vat_rate: number;
 }
 
@@ -284,10 +288,8 @@ function SortableOrderRow({
           <TextField
             label="Množství"
             type="number"
-            value={item.quantity}
-            onChange={(e) =>
-              onUpdate(index, "quantity", Number(e.target.value))
-            }
+            value={item.quantity ?? ""}
+            onChange={(e) => onUpdate(index, "quantity", e.target.value)}
             slotProps={{ htmlInput: { min: "0", step: "any" } }}
             InputProps={{ readOnly }}
           />
@@ -301,10 +303,8 @@ function SortableOrderRow({
           <TextField
             label="Jedn. cena"
             type="number"
-            value={item.unit_price}
-            onChange={(e) =>
-              onUpdate(index, "unit_price", Number(e.target.value))
-            }
+            value={item.unit_price ?? ""}
+            onChange={(e) => onUpdate(index, "unit_price", e.target.value)}
             slotProps={{ htmlInput: { step: "any" } }}
             InputProps={{ readOnly }}
           />
@@ -401,8 +401,8 @@ function SortableOrderRow({
       <TableCell>
         <TextField
           type="number"
-          value={item.quantity}
-          onChange={(e) => onUpdate(index, "quantity", Number(e.target.value))}
+          value={item.quantity ?? ""}
+          onChange={(e) => onUpdate(index, "quantity", e.target.value)}
           slotProps={{ htmlInput: { min: "0", step: "any" } }}
           InputProps={{ readOnly }}
           sx={{ "& input": { textAlign: "center" } }}
@@ -420,10 +420,8 @@ function SortableOrderRow({
       <TableCell>
         <TextField
           type="number"
-          value={item.unit_price}
-          onChange={(e) =>
-            onUpdate(index, "unit_price", Number(e.target.value))
-          }
+          value={item.unit_price ?? ""}
+          onChange={(e) => onUpdate(index, "unit_price", e.target.value)}
           slotProps={{ htmlInput: { step: "any" } }}
           InputProps={{ readOnly }}
           sx={{ "& input": { textAlign: "right" } }}
@@ -740,9 +738,11 @@ export default function IssuedOrderDetail() {
           .map((it, i) => ({
             description: it.description,
             item_description: it.item_description,
-            quantity: it.quantity,
+            // Coerce the raw typed strings back to numbers so an empty/partial
+            // field never reaches the server as NaN (mirrors the totals math).
+            quantity: Number(it.quantity) || 0,
             unit: it.unit,
-            unit_price: it.unit_price,
+            unit_price: Number(it.unit_price) || 0,
             vat_rate: it.vat_rate,
             position: i,
           })),
@@ -1135,7 +1135,7 @@ export default function IssuedOrderDetail() {
                           #
                         </TableCell>
                         <TableCell>Popis</TableCell>
-                        <TableCell sx={{ width: "5.5rem" }} align="center">
+                        <TableCell sx={{ width: "7rem" }} align="center">
                           Množství
                         </TableCell>
                         <TableCell sx={{ width: "5.5rem" }} align="center">
diff --git a/src/admin/pages/OfferDetail.tsx b/src/admin/pages/OfferDetail.tsx
index a5993fd..3c44df0 100644
--- a/src/admin/pages/OfferDetail.tsx
+++ b/src/admin/pages/OfferDetail.tsx
@@ -87,9 +87,12 @@ interface OfferItem {
   id?: number;
   description: string;
   item_description: string;
-  quantity: number;
+  // Held as the raw typed string while editing so the field can be cleared
+  // (an empty string renders fine in a type="number" input). Coerced via
+  // Number(x) || 0 only where used (live totals + save payload).
+  quantity: string | number;
   unit: string;
-  unit_price: number;
+  unit_price: string | number;
   is_included_in_total: boolean;
 }
 
@@ -323,10 +326,11 @@ function SortableItemRow({
           <TextField
             label="Množství"
             type="number"
-            value={item.quantity}
-            onChange={(e) => onUpdate("quantity", parseInt(e.target.value, 10))}
+            value={item.quantity ?? ""}
+            onChange={(e) => onUpdate("quantity", e.target.value)}
             slotProps={{ htmlInput: { step: "1" } }}
             InputProps={{ readOnly }}
+            sx={{ "& input": { textAlign: "center" } }}
           />
           <TextField
             label="Jednotka"
@@ -337,10 +341,11 @@ function SortableItemRow({
           <TextField
             label="Jedn. cena"
             type="number"
-            value={item.unit_price}
-            onChange={(e) => onUpdate("unit_price", parseFloat(e.target.value))}
+            value={item.unit_price ?? ""}
+            onChange={(e) => onUpdate("unit_price", e.target.value)}
             slotProps={{ htmlInput: { step: "0.01" } }}
             InputProps={{ readOnly }}
+            sx={{ "& input": { textAlign: "right" } }}
           />
         </Box>
         <Box
@@ -437,10 +442,11 @@ function SortableItemRow({
       <TableCell>
         <TextField
           type="number"
-          value={item.quantity}
-          onChange={(e) => onUpdate("quantity", parseInt(e.target.value, 10))}
+          value={item.quantity ?? ""}
+          onChange={(e) => onUpdate("quantity", e.target.value)}
           slotProps={{ htmlInput: { step: "1" } }}
           InputProps={{ readOnly }}
+          sx={{ "& input": { textAlign: "center" } }}
         />
       </TableCell>
       <TableCell>
@@ -453,10 +459,11 @@ function SortableItemRow({
       <TableCell>
         <TextField
           type="number"
-          value={item.unit_price}
-          onChange={(e) => onUpdate("unit_price", parseFloat(e.target.value))}
+          value={item.unit_price ?? ""}
+          onChange={(e) => onUpdate("unit_price", e.target.value)}
           slotProps={{ htmlInput: { step: "0.01" } }}
           InputProps={{ readOnly }}
+          sx={{ "& input": { textAlign: "right" } }}
         />
       </TableCell>
       <TableCell align="center">
@@ -882,7 +889,14 @@ export default function OfferDetail() {
       const url = isEdit ? `${API_BASE}/offers/${id}` : `${API_BASE}/offers`;
       const payload: any = {
         ...form,
-        items: items.map((item, i) => ({ ...item, position: i })),
+        items: items.map((item, i) => ({
+          ...item,
+          // Coerce the raw typed strings back to numbers so an empty/partial
+          // field never reaches the server as NaN (mirrors the totals math).
+          quantity: Number(item.quantity) || 0,
+          unit_price: Number(item.unit_price) || 0,
+          position: i,
+        })),
         sections: sections.map((s, i) => ({ ...s, position: i })),
       };
       if (!isEdit) delete payload.quotation_number;
@@ -1524,7 +1538,7 @@ export default function OfferDetail() {
                         #
                       </TableCell>
                       <TableCell>Popis</TableCell>
-                      <TableCell sx={{ width: "5.5rem" }} align="center">
+                      <TableCell sx={{ width: "7rem" }} align="center">
                         Množství
                       </TableCell>
                       <TableCell sx={{ width: "5rem" }}>Jednotka</TableCell>