diff --git a/po_runner.py b/po_runner.py
index e52e96b..a6a7719 100644
--- a/po_runner.py
+++ b/po_runner.py
@@ -13,6 +13,10 @@ from .po_modules.po_stations import PoStationReader
 from .po_modules.po_stations_qgs import PoStationReaderQgs
 from .po_modules.po_waterlevels_reader_qgs import PoWaterlevelReaderQgs
 
+STATIONS_QML = "styles/stations.qml"
+
+WATERLEVELS_QML = "styles/waterlevels.qml"
+
 
 class PoRunner(object):
 
@@ -134,10 +138,8 @@ class PoRunner(object):
         if self.stations is None:
             return
 
-        file = "styles/stations.qml"
-
         if self.ui.rbStationsStyleSimple == button:
-            self._layer_apply_style_from_file(self.stations, file)
+            self._layer_apply_style_from_file(self.stations, STATIONS_QML)
             return
         elif self.ui.rbStationsStyleAgency == button:
             field = "agency"
@@ -145,11 +147,11 @@ class PoRunner(object):
             field = "water"
         else:
             print("_bgStationsStyle_clicked: Style nicht implementiert: %s" % (button.objectName(),))
-            self._layer_apply_style_from_file(self.stations, file)
+            self._layer_apply_style_from_file(self.stations, STATIONS_QML)
             return
 
         self._stations_update_labels()
-        self._layer_apply_style_per_category(self.stations, field, file)
+        self._layer_apply_style_per_category(self.stations, field, STATIONS_QML)
 
     def _cbStationsVisible_toggled(self):
         visible = self.ui.cbStationsVisible.isChecked()
@@ -240,9 +242,8 @@ class PoRunner(object):
         if self.waterlevels is None:
             return
 
-        file = "styles/waterlevels.qml"
         if self.ui.rbWaterlevelsStyleSimple == button:
-            self._layer_apply_style_from_file(self.waterlevels, file)
+            self._layer_apply_style_from_file(self.waterlevels, WATERLEVELS_QML)
             return
         elif self.ui.rbWaterlevelsStyleAgency == button:
             field = "agency"
@@ -254,11 +255,11 @@ class PoRunner(object):
             field = "absolute"
         else:
             print("_bgWaterlevelsStyle_clicked: Style nicht implementiert: %s" % (button.objectName(),))
-            self._layer_apply_style_from_file(self.waterlevels, file)
+            self._layer_apply_style_from_file(self.waterlevels, WATERLEVELS_QML)
             return
 
         self._waterlevels_update_labels()
-        self._layer_apply_style_per_category(self.waterlevels, field, file)
+        self._layer_apply_style_per_category(self.waterlevels, field, WATERLEVELS_QML)
 
     def _cbWaterlevelsVisible_toggled(self):
         visible = self.ui.cbWaterlevelsVisible.isChecked()