diff --git a/__pycache__/custom_file_dialog.cpython-312.pyc b/__pycache__/custom_file_dialog.cpython-312.pyc
index 9648144..92a188a 100644
Binary files a/__pycache__/custom_file_dialog.cpython-312.pyc and b/__pycache__/custom_file_dialog.cpython-312.pyc differ
diff --git a/custom_file_dialog.py b/custom_file_dialog.py
index a16c916..c402c68 100644
--- a/custom_file_dialog.py
+++ b/custom_file_dialog.py
@@ -167,9 +167,9 @@ class CustomFileDialog(tk.Toplevel):
     def create_styles(self):
         style = ttk.Style(self)
         base_bg = self.cget('background')
-        is_dark = sum(self.winfo_rgb(base_bg)) / 3 < 32768
+        self.is_dark = sum(self.winfo_rgb(base_bg)) / 3 < 32768
 
-        if is_dark:
+        if self.is_dark:
             self.selection_color = "#4a6984"  # Darker blue for selection
             self.icon_bg_color = "#3c3c3c"     # Lighter background for content
             self.accent_color = "#2a2a2a"      # Darker accent for the bottom
@@ -219,7 +219,7 @@ class CustomFileDialog(tk.Toplevel):
                   ('selected', self.selection_color)])
         style.configure("Item.TLabel", background=self.icon_bg_color)
         style.map('Item.TLabel', background=[('selected', self.selection_color)], foreground=[
-                  ('selected', "black" if not is_dark else "white")])
+                  ('selected', "black" if not self.is_dark else "white")])
         style.configure("Icon.TLabel", background=self.icon_bg_color)
         style.map('Icon.TLabel', background=[
                   ('selected', self.selection_color)])
@@ -229,7 +229,7 @@ class CustomFileDialog(tk.Toplevel):
         style.configure("Treeview", rowheight=28,
                         background=self.icon_bg_color, fieldbackground=self.icon_bg_color, borderwidth=0)
         style.map("Treeview", background=[('selected', self.selection_color)], foreground=[
-                  ('selected', "black" if not is_dark else "white")])
+                  ('selected', "black" if not self.is_dark else "white")])
 
         style.configure("TButton.Borderless.Round", anchor="w")
 
@@ -295,7 +295,8 @@ class CustomFileDialog(tk.Toplevel):
         Tooltip(self.hidden_files_button, "Versteckte Dateien anzeigen")
 
         # Horizontal separator
-        ttk.Separator(main_frame, orient='horizontal').grid(
+        separator_color = "#000000" if self.is_dark else "#d9d9d9"
+        tk.Frame(main_frame, height=1, bg=separator_color).grid(
             row=1, column=0, sticky="ew")
 
         # Paned window for sidebar and content
@@ -332,7 +333,8 @@ class CustomFileDialog(tk.Toplevel):
                              compound="left", command=lambda p=config['path']: self.navigate_to(p), style="Dark.TButton.Borderless")
             btn.pack(fill="x", pady=1)
 
-        ttk.Separator(sidebar_buttons_frame, orient='horizontal').pack(fill='x', pady=10, padx=20)
+        ttk.Separator(sidebar_buttons_frame, orient='horizontal').pack(
+            fill='x', pady=10, padx=20)
 
         storage_frame = ttk.Frame(sidebar_frame, style="Sidebar.TFrame")
         storage_frame.grid(row=1, column=0, sticky="ew", padx=10)
@@ -372,7 +374,7 @@ class CustomFileDialog(tk.Toplevel):
                    command=self.on_cancel).grid(row=1, column=0, padx=10)
 
         self.filter_combobox = ttk.Combobox(
-            bottom_controls_frame, values=[ft[0] for ft in self.filetypes], state="readonly", width=20)
+            bottom_controls_frame, values=[ft[0] for ft in self.filetypes], state="readonly")
         self.filter_combobox.grid(
             row=1, column=1, sticky="w", padx=10, pady=(5, 10))
         self.filter_combobox.bind(
diff --git a/mainwindow.py b/mainwindow.py
index 1bd756d..0610908 100644
--- a/mainwindow.py
+++ b/mainwindow.py
@@ -58,7 +58,7 @@ if __name__ == "__main__":
     style = ttk.Style(root)
     root.tk.call('source', f"{theme_path}/water.tcl")
     try:
-        root.tk.call('set_theme', 'dark')
+        root.tk.call('set_theme', 'light')
     except tk.TclError:
         pass
     root.mainloop()