diff --git a/video_concat.py b/video_concat.py
index edcb80b..59ca8f5 100755
--- a/video_concat.py
+++ b/video_concat.py
@@ -14,88 +14,76 @@ ctk.set_default_color_theme("blue") # "blue" | "green" | "dark-blue"
 class VideoConcatenatorApp(ctk.CTk):
     def __init__(self):
         super().__init__()
-        self.title("Video Concatenator (CustomTkinter)")
-        self.geometry("700x700")
+        self.title("Video Concatenator")
+        self.geometry("800x800")
+
+        # DPI scaling
+        dpi = self.winfo_fpixels('1i') / 72
+        self.tk.call('tk', 'scaling', dpi)
+        base_font = int(12 * dpi)
 
         # State
         self.selected_files = []
         self.output_file_name = "output.mp4"
         self.delete_original = tk.BooleanVar(value=False)
         self.output_dir = ""
-        # detect ffmpeg.exe
         self.ffmpeg_path = shutil.which("ffmpeg")
 
-        # 1. Select Video Files
-        self.label1 = ctk.CTkLabel(self, text="1. Select Video Files", font=("Arial", 14))
+        # 1. Select and Order Videos
+        self.label1 = ctk.CTkLabel(self, text="1. Select and Order Videos", font=(None, base_font+4))
         self.label1.pack(pady=(10,5))
-        self.select_btn = ctk.CTkButton(self, text="Select Videos", command=self.select_videos)
+        self.select_btn = ctk.CTkButton(self, text="Select Videos", command=self.select_videos, font=(None, base_font))
         self.select_btn.pack(pady=5)
 
-        # Listbox frame
+        # Listbox for files with drag-and-drop
         self.listbox_frame = ctk.CTkFrame(self)
-        self.listbox_frame.pack(pady=5, fill="x", expand=False)
-        self.files_listbox = tk.Listbox(self.listbox_frame, selectmode=tk.SINGLE, width=80, height=8)
+        self.listbox_frame.pack(pady=5, fill="both", expand=True)
+        self.files_listbox = tk.Listbox(self.listbox_frame, selectmode=tk.SINGLE)
         self.files_listbox.pack(padx=5, pady=5, fill="both", expand=True)
+        self.files_listbox.bind('<Button-1>', self.on_drag_start)
+        self.files_listbox.bind('<B1-Motion>', self.on_drag_motion)
 
-        # 2. Organize sequence
-        self.label2 = ctk.CTkLabel(self, text="2. Organize Sequence", font=("Arial", 14))
+        # 2. Name the Output File
+        self.label2 = ctk.CTkLabel(self, text="2. Name the Output File", font=(None, base_font+4))
         self.label2.pack(pady=(10,5))
-        self.up_down_frame = ctk.CTkFrame(self)
-        self.up_down_frame.pack(pady=5)
-        self.up_btn = ctk.CTkButton(self.up_down_frame, text="Move Up", command=self.move_up)
-        self.up_btn.grid(row=0, column=0, padx=10, pady=5)
-        self.down_btn = ctk.CTkButton(self.up_down_frame, text="Move Down", command=self.move_down)
-        self.down_btn.grid(row=0, column=1, padx=10, pady=5)
-
-        # 3. Name the Output File
-        self.label3 = ctk.CTkLabel(self, text="3. Name the Output File", font=("Arial", 14))
-        self.label3.pack(pady=(10,5))
-        self.output_name_entry = ctk.CTkEntry(self, width=300)
+        self.output_name_entry = ctk.CTkEntry(self, width=0)
+        self.output_name_entry.pack(pady=5, fill="x", expand=True)
         self.output_name_entry.insert(0, self.output_file_name)
-        self.output_name_entry.pack(pady=5)
-
-        # Inline name-conflict warning
-        self.name_warning_label = ctk.CTkLabel(
-            self,
-            text="",
-            text_color="red",
-            font=("Arial", 12)
-        )
-        self.name_warning_label.pack(pady=(0,5))
-
-        # Bind to update warning and button state on typing
         self.output_name_entry.bind("<KeyRelease>", self.check_name_conflict)
 
-        # 4. Select Output Directory
-        self.label4 = ctk.CTkLabel(self, text="4. Select Output Directory", font=("Arial", 14))
-        self.label4.pack(pady=(10,5))
-        self.output_dir_btn = ctk.CTkButton(self, text="Choose Output Directory", command=self.select_output_dir)
-        self.output_dir_btn.pack(pady=5)
-        self.output_dir_label = ctk.CTkLabel(self, text="", text_color="blue")
-        self.output_dir_label.pack(pady=5)
+        self.name_warning_label = ctk.CTkLabel(self, text="", text_color="red", font=(None, base_font))
+        self.name_warning_label.pack(pady=(0,5))
 
-        # 5. Delete original files option
+        # 3. Select Output Directory
+        self.label3 = ctk.CTkLabel(self, text="3. Select Output Directory", font=(None, base_font+4))
+        self.label3.pack(pady=(10,5))
+        self.output_dir_btn = ctk.CTkButton(self, text="Choose Output Directory", command=self.select_output_dir, font=(None, base_font))
+        self.output_dir_btn.pack(pady=5)
+        self.output_dir_label = ctk.CTkLabel(self, text="", text_color="blue", font=(None, base_font))
+        self.output_dir_label.pack(pady=5, fill="x", expand=True)
+
+        # Delete original option
         self.delete_original_check = ctk.CTkCheckBox(
             self,
             text="Delete Original Files After Concatenation",
-            variable=self.delete_original
+            variable=self.delete_original,
+            font=(None, base_font)
         )
         self.delete_original_check.pack(pady=5)
 
         # Concatenate Button
-        self.concat_btn = ctk.CTkButton(self, text="Concatenate Videos", command=self.start_concatenation, state="disabled")
+        self.concat_btn = ctk.CTkButton(self, text="Concatenate Videos", command=self.start_concatenation, state="disabled", font=(None, base_font+2))
         self.concat_btn.pack(pady=10)
 
         # Time Left Label
-        self.time_left_label = ctk.CTkLabel(self, text="", font=("Arial", 12), text_color="green")
+        self.time_left_label = ctk.CTkLabel(self, text="", font=(None, base_font+2), text_color="green")
         self.time_left_label.pack(pady=5)
 
-        # If ffmpeg not found, disable concatenation
+        # Disable if ffmpeg missing
         if not self.ffmpeg_path:
             messagebox.showerror(
                 "Missing Dependency",
-                "Could not find ffmpeg on your system.\n"
-                "Please install ffmpeg and make sure it's on your PATH."
+                "ffmpeg not found. Please install and add it to PATH."
             )
             self.concat_btn.configure(state="disabled")
 
@@ -105,153 +93,102 @@ class VideoConcatenatorApp(ctk.CTk):
         )
         if files:
             self.selected_files = list(files)
-            self.update_files_listbox()
-
-            # Auto-fill output name from the first file
-            first_file = os.path.basename(self.selected_files[0])
-            default_name = os.path.splitext(first_file)[0] + ".mp4"
+            self.refresh_listbox()
+            # autofill name
+            first = os.path.basename(self.selected_files[0])
+            default = os.path.splitext(first)[0] + ".mp4"
             self.output_name_entry.delete(0, tk.END)
-            self.output_name_entry.insert(0, default_name)
-
-            # Re-check for conflicts and button state
+            self.output_name_entry.insert(0, default)
             self.check_name_conflict()
 
-            # Only enable if no conflict and ffmpeg exists
-            if self.ffmpeg_path and not self._has_name_conflict():
-                self.concat_btn.configure(state="normal")
-
-    def update_files_listbox(self):
+    def refresh_listbox(self):
         self.files_listbox.delete(0, tk.END)
         for f in self.selected_files:
             self.files_listbox.insert(tk.END, f)
 
-    def move_up(self):
-        sel = self.files_listbox.curselection()
-        if sel and sel[0] > 0:
-            i = sel[0]
-            self.selected_files[i-1], self.selected_files[i] = self.selected_files[i], self.selected_files[i-1]
-            self.update_files_listbox()
-            self.files_listbox.select_set(i-1)
+    def on_drag_start(self, event):
+        self.drag_start = self.files_listbox.nearest(event.y)
 
-    def move_down(self):
-        sel = self.files_listbox.curselection()
-        if sel and sel[0] < len(self.selected_files)-1:
-            i = sel[0]
-            self.selected_files[i+1], self.selected_files[i] = self.selected_files[i], self.selected_files[i+1]
-            self.update_files_listbox()
-            self.files_listbox.select_set(i+1)
+    def on_drag_motion(self, event):
+        i = self.files_listbox.nearest(event.y)
+        if i != self.drag_start:
+            # swap
+            self.selected_files[self.drag_start], self.selected_files[i] = (
+                self.selected_files[i], self.selected_files[self.drag_start]
+            )
+            self.refresh_listbox()
+            self.files_listbox.select_set(i)
+            self.drag_start = i
 
     def select_output_dir(self):
         d = filedialog.askdirectory()
         if d:
             self.output_dir = d
             self.output_dir_label.configure(text=d)
+            self.check_name_conflict()
 
     def _has_name_conflict(self):
         name = self.output_name_entry.get().strip()
-        base_name = os.path.splitext(name)[0]
-        return any(
-            os.path.splitext(os.path.basename(f))[0] == base_name
-            for f in self.selected_files
-        )
+        base = os.path.splitext(name)[0]
+        return any(os.path.splitext(os.path.basename(f))[0] == base for f in self.selected_files)
 
     def check_name_conflict(self, event=None):
-        """
-        Show warning and disable/enable the concat button based on name conflict.
-        """
         conflict = self._has_name_conflict()
         if conflict:
-            self.name_warning_label.configure(
-                text="⚠️ This name matches one of your originals!"
-            )
+            self.name_warning_label.configure(text="⚠️ Name matches an original file.")
             self.concat_btn.configure(state="disabled")
         else:
             self.name_warning_label.configure(text="")
-            # Only re-enable if videos are selected and ffmpeg exists
-            if self.selected_files and self.ffmpeg_path:
+            if self.selected_files and self.output_dir and self.ffmpeg_path:
                 self.concat_btn.configure(state="normal")
 
     def start_concatenation(self):
         self.concat_btn.configure(state="disabled")
-        self.time_left_label.configure(text="Starting concatenation...")
+        self.time_left_label.configure(text="Starting...")
         threading.Thread(target=self.concatenate_videos).start()
 
     def concatenate_videos(self):
-        # sanity checks
+        # checks
         if not self.selected_files:
             messagebox.showerror("Error", "No videos selected.")
-            self.concat_btn.configure(state="normal")
             return
         if not self.output_dir:
             messagebox.showerror("Error", "Output directory not selected.")
-            self.concat_btn.configure(state="normal")
             return
+        name = self.output_name_entry.get().strip() or self.output_file_name
+        if not name.lower().endswith('.mp4'):
+            name += '.mp4'
+        outp = os.path.join(self.output_dir, name)
 
-        # get output file name
-        outname = self.output_name_entry.get().strip()
-        if not outname:
-            messagebox.showerror("Error", "Output file name cannot be empty.")
-            self.concat_btn.configure(state="normal")
-            return
-        if not outname.lower().endswith(".mp4"):
-            outname += ".mp4"
-
-        output_file = os.path.join(self.output_dir, outname)
-
-        # build the file list
-        list_path = os.path.join(self.output_dir, "file_list.txt")
-        with open(list_path, "w", encoding="utf-8") as f:
+        list_path = os.path.join(self.output_dir, 'file_list.txt')
+        with open(list_path, 'w', encoding='utf-8') as f:
             for file in self.selected_files:
-                path = file.replace("\\", "/").replace("'", r"'\\''")
-                f.write(f"file '{path}'\n")
+                p = file.replace('\\', '/').replace("'", "'\\''")
+                f.write(f"file '{p}'\n")
 
-        cmd = [
-            self.ffmpeg_path,
-            "-y",
-            "-f", "concat",
-            "-safe", "0",
-            "-i", "file_list.txt",
-            "-c:v", "copy",
-            "-c:a", "copy",
-            output_file
-        ]
+        cmd = [self.ffmpeg_path, '-y', '-f', 'concat', '-safe', '0', '-i', 'file_list.txt', '-c:v', 'copy', '-c:a', 'copy', outp]
 
-        # estimate time
-        estimate = len(self.selected_files) * 5
-        for i in range(estimate):
+        # estimated time
+        for sec in range(len(self.selected_files)*5):
             time.sleep(1)
-            self.time_left_label.configure(text=f"Estimated time left: {estimate - i}s")
+            self.time_left_label.configure(text=f"Est. time left: {len(self.selected_files)*5 - sec}s")
             self.update_idletasks()
 
-        # run ffmpeg
-        proc = subprocess.run(
-            cmd,
-            stdout=subprocess.PIPE,
-            stderr=subprocess.PIPE,
-            text=True,
-            cwd=self.output_dir
-        )
-
+        proc = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True, cwd=self.output_dir)
         if proc.returncode != 0:
             self.time_left_label.configure(text="Error during concatenation.")
-            messagebox.showerror("FFmpeg error", proc.stderr.strip())
+            messagebox.showerror("FFmpeg error", proc.stderr)
         else:
-            self.time_left_label.configure(text="Concatenation completed!")
-            messagebox.showinfo("Success", f"Output: {output_file}")
-
+            self.time_left_label.configure(text="Done!")
+            messagebox.showinfo("Success", f"Output saved to: {outp}")
             if self.delete_original.get():
-                for file in self.selected_files:
-                    try:
-                        os.remove(file)
-                    except OSError:
-                        pass
-                messagebox.showinfo("Info", "Original files have been deleted.")
-
-        # cleanup & re-enable
-        if os.path.exists(list_path):
-            os.remove(list_path)
+                for f in self.selected_files:
+                    try: os.remove(f)
+                    except: pass
+                messagebox.showinfo("Info", "Original files deleted.")
+        if os.path.exists(list_path): os.remove(list_path)
         self.concat_btn.configure(state="normal")
 
-if __name__ == "__main__":
+if __name__ == '__main__':
     app = VideoConcatenatorApp()
-    app.mainloop()   
\ No newline at end of file
+    app.mainloop()