go/svc/invoice: polishify
diff --git a/go/svc/invoice/render.go b/go/svc/invoice/render.go
index 47c6c6d..a433fa8 100644
--- a/go/svc/invoice/render.go
+++ b/go/svc/invoice/render.go
@@ -72,7 +72,10 @@
 		InvoiceeBilling: make([]string, len(i.CustomerBilling)),
 	}
 
-	unit := "€"
+	unit := i.Unit
+	if unit == "" {
+		unit = "€"
+	}
 
 	for d, s := range i.InvoicerBilling {
 		data.InvoicerBilling[d] = s
diff --git a/go/svc/invoice/templates/invoice.html b/go/svc/invoice/templates/invoice.html
index e257a42..6bf2947 100644
--- a/go/svc/invoice/templates/invoice.html
+++ b/go/svc/invoice/templates/invoice.html
@@ -105,16 +105,16 @@
                     {{ end }}
                     {{ end }}
                     {{ if .InvoicerCompanyNumber }}
-                    <li><b>Company Registration Number:</b> {{ .InvoicerCompanyNumber }}</li>
+                    <li>{{ .InvoicerCompanyNumber }}</li>
                     {{ end }}
-                    <li><b>Tax Number:</b> {{ .InvoicerVAT }}</li>
+                    <li><b>NIP:</b> {{ .InvoicerVAT }}</li>
                 </ul>
             </div>
             <div class="metadata">
                 <ul>
-                    <li><b>Invoice number:</b> {{ .InvoiceNumber }}</li>
-                    <li><b>Date:</b> {{ .Date.Format "2006/01/02" }}</li>
-                    <li><b>Due date:</b> {{ .DueDate.Format "2006/01/02" }}</li>
+                    <li><b>Numer faktury:</b> {{ .InvoiceNumber }}</li>
+                    <li><b>Data wystawienia:</b> {{ .Date.Format "2006/01/02" }}</li>
+                    <li><b>Termin płatności:</b> {{ .DueDate.Format "2006/01/02" }}</li>
                     <li><b>IBAN:</b> {{ .IBAN }}</li>
                     <li><b>SWIFT/BIC:</b> {{ .SWIFT }}</li>
                 </ul>
@@ -123,9 +123,9 @@
         <div class="lhs">
             <div class="invoicee">
                 {{ if .Proforma }}
-                <h1>Proforma Invoice:</h1>
+                <h1>Faktura proforma:</h1>
                 {{ else }}
-                <h1>VAT Invoice:</h1>
+                <h1>Faktura VAT:</h1>
                 {{ end }}
                 <ul>
                     {{ range $i, $e := .InvoiceeBilling }}
@@ -139,7 +139,7 @@
                     <li>EIN: {{ .InvoiceeVAT }}</li>
                     <li><b>(VAT zero rate)</b></li>
                     {{ else }}
-                    <li>VAT Number: {{ .InvoiceeVAT }}</li>
+                    <li><b>NIP:</b> {{ .InvoiceeVAT }}</li>
                     {{ end }}
 
                     {{ if .ReverseVAT }}
@@ -151,12 +151,12 @@
         <div style="clear: both; height: 1em;"></div>
         <table class="items">
             <tr>
-                <th style="width: 60%;">Description</th>
-                <th>Price<br/>(ex. VAT)</th>
-                <th>Qty</th>
-                <th>VAT rate</th>
-                <th>Total<br />(net)</th>
-                <th>Total<br />(inc. VAT)</th>
+                <th style="width: 60%;">Nazwa towaru lub usługi</th>
+                <th>Cena<br />netto</th>
+                <th>Ilość</th>
+                <th>VAT (%)</th>
+                <th>Wartość<br />netto</th>
+                <th>Wartość<br />brutto</th>
             </tr>
             {{ range .Items }}
             <tr>
@@ -169,16 +169,16 @@
             </tr>
             {{ end }}
             <tr>
-                <td colspan="5" class="lhead">Subtotal without VAT</td>
+                <td colspan="5" class="lhead">RAZEM netto</td>
                 <td>{{ .TotalNet }}</td>
             </tr>
             <tr>
-                <td colspan="5" class="lhead">VAT Total{{ if .ReverseVAT }} (reverse charge applies){{ end }} {{ if .USCustomer }}(VAT zero rate){{ end }}</td>
+                <td colspan="5" class="lhead">VAT{{ if .ReverseVAT }} (reverse charge applies){{ end }} {{ if .USCustomer }}(VAT zero rate){{ end }}</td>
                 <td>{{ .VATTotal }}</td>
             </tr>
             <tr>
-                <td colspan="5" class="lhead"><b>Total</b></td>
-                <td>{{ .Total }}</td>
+                <td colspan="5" class="lhead"><b>RAZEM brutto</b></td>
+                <td><b>{{ .Total }}</b></td>
             </tr>
         </table>
     </body>
diff --git a/proto/invoice/invoice.proto b/proto/invoice/invoice.proto
index e56253d..90fc874 100644
--- a/proto/invoice/invoice.proto
+++ b/proto/invoice/invoice.proto
@@ -29,6 +29,7 @@
     int64 days_due = 8;
     string iban = 9;
     string swift = 10;
+    string unit = 13;
 }
 
 message CreateInvoiceRequest {