Tasks: Replace ttk.Frame with tk.Frame in LoginWindow

Implementation Tasks

1. [x] Replace main_frame with tk.Frame (image_generator.py:147)

   • Change main_frame = ttk.Frame(self.root, padding=40)
   • To main_frame = tk.Frame(self.root, bg='white', padx=40, pady=40)
   • Validation: main_frame should have white background on macOS

2. [x] Replace username_frame with tk.Frame (image_generator.py:157)

   • Change username_frame = ttk.Frame(main_frame)
   • To username_frame = tk.Frame(main_frame, bg='white')
   • Validation: Frame renders with white background

3. [x] Replace password_frame with tk.Frame (image_generator.py:176)

   • Change password_frame = ttk.Frame(main_frame)
   • To password_frame = tk.Frame(main_frame, bg='white')
   • Validation: Frame renders with white background

4. [x] Replace checkbox_frame with tk.Frame (image_generator.py:204)

   • Change checkbox_frame = ttk.Frame(main_frame)
   • To checkbox_frame = tk.Frame(main_frame, bg='white')
   • Validation: Frame renders with white background

5. [ ] Test complete UI visibility on macOS

   • Verify title "登录" is visible
   • Verify username label and Entry are visible
   • Verify password label and Entry are visible
   • Verify checkboxes remain visible
   • Verify login button is visible
   • Validation: Take screenshot showing all elements visible

6. Cross-platform verification

   • Test on Windows (ensure no visual regression)
   • Test on Linux if available (ensure no visual regression)
   • Validation: UI renders consistently across platforms

7. Functional testing

   • Test typing in both input fields
   • Test login button click
   • Test checkbox toggling
   • Test tab navigation
   • Validation: All interactions work correctly

Dependencies

• Tasks 1-4 can be completed in a single edit session
• Tasks 5-7 require manual testing after implementation

Notes

• Keep ttk.Button for login button (works fine)
• All tk.Frame widgets MUST have explicit bg='white'
• This is a minimal change - just widget type replacement