added new warning

frontend/src/pages/MainForm.tsx

@@ -102,6 +102,12 @@ export const MainForm = () => {
     const savedUser = Cookies.get("selectedUser");
     if (savedUser) {
       setSelectedUser(savedUser);
+    } else {
+      setMsg({
+        type: "warning",
+        headline: t("set-username-headline"),
+        text: t("set-username-text")
+      })
     }
   }, []);
 
@@ -442,10 +448,16 @@ export const MainForm = () => {
               </Button>
             )}
 
-            {/* Alert message */}
+            {/* Message */}
             {msg && (
-              <Alert color={msg.type} sx={{ borderRadius: "12px" }}>
-                <strong>{msg.headline}:</strong> {msg.text}
+              <Alert
+                color={msg.type}
+                sx={{ flexDirection: "column", alignItems: "flex-start" }}
+              >
+                <Typography level="title-lg" sx={{ mb: 0.5 }}>
+                  {msg.headline}
+                </Typography>
+                <Typography level="body-sm">{msg.text}</Typography>
               </Alert>
             )}
           </form>

frontend/src/utils/i18n/locales/de/de.json

@@ -28,5 +28,7 @@
     "return-to-homepage": "Zurück",
     "qr-text": "PayPal QR-Code der Claudius Akademie",
     "loading": "Lädt...",
-    "greeting": "Hallo,"
+    "greeting": "Hallo,",
+    "set-username-headline": "Keinen Benutzer ausgewählt",
+    "set-username-text": "Um mit dem Losverkauf zu beginnen, musst du einen Benutzer oben links auswählen."
 }

frontend/src/utils/i18n/locales/en/en.json

@@ -29,5 +29,7 @@
     "return-to-homepage": "Return",
     "qr-text": "PayPal QR-Code from the Claudius Akademie",
     "loading": "Loading...",
-    "greeting": "Hello,"
+    "greeting": "Hello,",
+    "set-username-headline": "No user selected",
+    "set-username-text": "To start the ticket sale, you must select a user first from the top left."
 }