fix(teams): ensure dark theme styling on group member role select dropdown

frontend/src/features/teams/GroupsView.tsx

@@ -510,15 +510,15 @@ export const GroupsView: React.FC<GroupsViewProps> = ({ currentUser, onBack }) =
                                           e.target.value as 'admin' | 'member'
                                         )
                                       }
-                                    className={`h-6 px-1.5 text-[10px] rounded border ${
+                                      className={`h-6 px-1.5 text-[10px] rounded input-field bg-panel cursor-pointer ${
                                         isAdmin
-                                        ? 'bg-accent/15 border-accent/40 text-accent font-semibold'
+                                          ? 'border-accent text-accent font-semibold'
-                                        : 'bg-canvas border-border text-muted'
+                                          : 'text-muted'
                                       }`}
                                       title="Rolle ändern"
                                     >
-                                    <option value="member">Mitglied</option>
+                                      <option value="member" className="bg-panel text-main">Mitglied</option>
-                                    <option value="admin">Gruppen-Admin</option>
+                                      <option value="admin" className="bg-panel text-main">Gruppen-Admin</option>
                                     </select>
 
                                   <button