无法将框架放在tkinter的底部

Question

我想知道为什么以下内容不会将底部框架放在根窗口的底部。我的预期结果是

     cyan
     red
black | green
     white

import tkinter as tk

root = tk.Tk()
w, h = root.winfo_screenwidth(), root.winfo_screenheight()
root.state('zoomed')
root.geometry("%dx%d+0+0" % (w-15, h-75))
top = tk.Frame(root, bg='cyan')
top.pack(fill=tk.BOTH, expand=tk.TRUE)
top2 = tk.Frame(root, bg='red')
top2.pack(fill=tk.BOTH, expand=tk.TRUE)

right = tk.Frame(root, bg='lightgreen')
right.pack(side=tk.RIGHT, fill=tk.BOTH, expand=tk.TRUE)

left = tk.Frame(root, bg='black')
left.pack(side=tk.LEFT, fill=tk.BOTH, expand=tk.TRUE)

bottom = tk.Frame(root, bg='white')
bottom.pack(side=tk.BOTTOM, fill=tk.BOTH, expand=tk.TRUE)

root.mainloop()