diff --git a/source/galaxy-flasher-gtk.py b/source/galaxy-flasher-gtk.py
index 89b7922..0a069d8 100755
--- a/source/galaxy-flasher-gtk.py
+++ b/source/galaxy-flasher-gtk.py
@@ -469,7 +469,7 @@ def set_selected_device(btn, device):
                 "command": lambda _: self.ft_plugin.selected_device(
                     self, device_number, len(devices)
                 ),
-                "add-css-classes": ["suggested-action"],
+                "add_css_classes": ["suggested-action"],
             },
             {
                 "title": "Cancel",
@@ -532,7 +532,7 @@ def partition_toggled(button, row):
                 "command": lambda _: function(
                     self, selected_partitions
                 ),
-                "add-css-classes": ["suggested-action"],
+                "add_css_classes": ["suggested-action"],
             },
             {
                 "title": "Cancel",
@@ -640,7 +640,7 @@ def display_done_flashing(self):
                 {
                     "title": "OK",
                     "command": lambda _: self.stack.set_visible_child_full("start", Gtk.StackTransitionType.SLIDE_RIGHT),
-                    "add-css-classes": ["suggested-action"],
+                    "add_css_classes": ["suggested-action"],
                 },
             ]
 
@@ -1640,4 +1640,4 @@ def do_activate(self):
 
 if __name__ == "__main__":
     app = GalaxyFlasherGtk(application_id="page.codeberg.ethicalhaquer.galaxyflasher")
-    app.run(sys.argv)
+    app.run(sys.argv)
\ No newline at end of file