Windows compatibility

page_splitter.py

@@ -1,16 +1,17 @@
-import fitz  # PyMuPDF
-import tkinter as tk
-from tkinter import messagebox
-from PIL import Image, ImageTk, ImageDraw
-import sys
+import glob
 import os
 import re
-import glob
 import shutil
-import subprocess
+import sys
+import tkinter as tk
+from tkinter import messagebox
+
+import fitz  # PyMuPDF
+from PIL import Image, ImageDraw, ImageTk
 from pypdf import PdfReader, PdfWriter
 
 from config import PAGE_SPLITTER_KB
+from platform_utils import launch_pdf_arranger
 
 
 # --- Constants ---
@@ -169,7 +170,10 @@ class PDFPreviewer:
         self.current_zoom = 1.0
 
     def start_arranger(self):
-        subprocess.Popen(["pdf-arranger", self.pdf_path])
+        try:
+            launch_pdf_arranger(self.pdf_path)
+        except FileNotFoundError as exc:
+            messagebox.showerror("PDF Arranger", str(exc))
 
     def on_resize(self, event):
         """