diff --git a/app.py b/app.py
index b4e2379..24ab722 100644
--- a/app.py
+++ b/app.py
@@ -75,15 +75,30 @@ with col1:
         input_path = Path(app_config.input_dir) / selected_input
         # Validiere und parse sofort
         with st.spinner("Validiere Input-Datei…"):
-            val_result = validate_input_file(input_path, app_config.input_schema)
+            val_result = validate_input_file(input_path, app_config.input_schema, app_config.month_sheet_pattern)
 
         if not val_result.is_valid:
+            st.markdown(
+                '<div style="border:2px solid #e74c3c; border-radius:8px; padding:12px; '
+                'background:#fdedec; margin-bottom:12px">'
+                '<span style="color:#b03a2e; font-weight:bold; font-size:1.1em">'
+                '❌ Validierung fehlgeschlagen</span></div>',
+                unsafe_allow_html=True,
+            )
             for err in val_result.errors:
-                st.error(err)
+                st.error(f"🔴 {err}")
             st.session_state.input_validated = False
         else:
-            for warn in val_result.warnings:
-                st.warning(warn)
+            if val_result.warnings:
+                st.markdown(
+                    '<div style="border:2px solid #f39c12; border-radius:8px; padding:8px 12px; '
+                    'background:#fef9e7; margin-bottom:8px">'
+                    '<span style="color:#7d6608; font-weight:bold">'
+                    '⚠️ Hinweise</span></div>',
+                    unsafe_allow_html=True,
+                )
+                for warn in val_result.warnings:
+                    st.warning(warn)
 
             # Parse die Datei
             records = parse_input_file(
@@ -130,8 +145,15 @@ with col2:
             tpl_result = validate_template(template_path, app_config.output_mapping)
 
         if not tpl_result.is_valid:
+            st.markdown(
+                '<div style="border:2px solid #e74c3c; border-radius:8px; padding:12px; '
+                'background:#fdedec; margin-bottom:12px">'
+                '<span style="color:#b03a2e; font-weight:bold; font-size:1.1em">'
+                '❌ Validierung fehlgeschlagen</span></div>',
+                unsafe_allow_html=True,
+            )
             for err in tpl_result.errors:
-                st.error(err)
+                st.error(f"🔴 {err}")
             st.session_state.template_validated = False
         else:
             st.session_state.template_validated = True
@@ -139,6 +161,13 @@ with col2:
             total = tpl_result.info.get("total_target_cells", 0)
             st.success(f"✅ {found}/{total} Zielfelder gefunden")
             if tpl_result.warnings:
+                st.markdown(
+                    '<div style="border:2px solid #f39c12; border-radius:8px; padding:8px 12px; '
+                    'background:#fef9e7; margin-bottom:8px">'
+                    '<span style="color:#7d6608; font-weight:bold">'
+                    '⚠️ Hinweise</span></div>',
+                    unsafe_allow_html=True,
+                )
                 for warn in tpl_result.warnings:
                     st.warning(warn)
 
diff --git a/src/parser.py b/src/parser.py
index de3b39b..289d58a 100644
--- a/src/parser.py
+++ b/src/parser.py
@@ -65,7 +65,9 @@ def parse_input_file(
 
         ws = wb[sheet_name]
         # Header ist Zeile 1, Daten ab Zeile 2
-        for row in ws.iter_rows(min_row=2, max_row=ws.max_row, values_only=True):
+        # min_col=1 explizit setzen für korrekte Spaltenzuordnung
+        schema_col_count = len(schema)
+        for row in ws.iter_rows(min_row=2, max_row=ws.max_row, min_col=1, max_col=schema_col_count, values_only=True):
             name = _to_text(row[col_map.get("Name", 0)]) if len(row) > col_map.get("Name", 0) else ""
             antragsnummer = _to_text(row[col_map.get("Antragsnummer", 0)]) if len(row) > col_map.get("Antragsnummer", 0) else ""
 
diff --git a/src/validator.py b/src/validator.py
index 2b038f6..4d42c81 100644
--- a/src/validator.py
+++ b/src/validator.py
@@ -6,18 +6,21 @@ from typing import Optional
 from openpyxl import load_workbook
 from openpyxl.utils import column_index_from_string
 
+from .config import is_month_sheet
 from .models import FieldSchema, OutputMapping, ValidationResult
 
 
 def validate_input_file(
     filepath: Path,
     schema: list[FieldSchema],
+    month_sheet_pattern: str = "* 20??",
 ) -> ValidationResult:
     """
     Validiert eine Input-Datei:
     - Datei existiert
     - Erwartete Spalten sind vorhanden (Header in Zeile 1)
-    - Mindestens ein Daten-Sheet enthält Daten
+    - Mindestens ein Monats-Daten-Sheet enthält Daten
+    - Nicht-Monats-Sheets (z. B. "Alle Rollen") werden übersprungen
     """
     errors: list[str] = []
     warnings: list[str] = []
@@ -37,14 +40,23 @@ def validate_input_file(
     info["sheet_count"] = sheet_count
     info["sheet_names"] = wb.sheetnames
 
-    # Prüfe, ob mindestens ein Sheet die erwarteten Spalten hat
+    # Prüfe nur Monats-Sheets (überspringe z. B. "Alle Rollen")
+    schema_col_count = len(schema)
     sheets_with_data = 0
     for sheet_name in wb.sheetnames:
+        if not is_month_sheet(sheet_name, month_sheet_pattern):
+            continue
+
         ws = wb[sheet_name]
         if ws.max_row < 2:
             continue  # Kein Header + Daten
 
-        header_row = list(ws.iter_rows(min_row=1, max_row=1, values_only=True))[0]
+        # min_col=1 explizit setzen, um Verschiebungen bei
+        # ws.min_column > 1 zu vermeiden
+        header_row = list(ws.iter_rows(
+            min_row=1, max_row=1, min_col=1, max_col=schema_col_count,
+            values_only=True,
+        ))[0]
         missing_cols = []
         for field in schema:
             col_idx = column_index_from_string(field.column) - 1