似乎无法在tkinter中更改窗口背景颜色

Question

到目前为止，这是我在tkinter中制作的GUI的代码，我试图更改窗口的背景颜色，但似乎不起作用。

from tkinter import *
from tkinter.font import Font

class Window(Frame):

    def __init__(self, master = None):
        Frame.__init__(self, master)
        self.master = master
        self.init_window()

    def init_window(self):
        self.master.title("Main Menu")
        self.pack(fill=BOTH, expand=1)

    videoButton = Button(self, text="Video Mode", font=helv18, bg="white", height=1, width=18)
    videoButton.place(relx=0.5, rely=0.35, anchor=CENTER)

    timelapseButton = Button(self, text="Time-lapse Mode", font=helv18, bg="white", height=1, width=18)
    timelapseButton.place(relx=0.5, rely=0.6, anchor=CENTER)

root = Tk()

helv18 = Font(family='Helvetica', size=18, weight='bold')

root.config(bg='black')
root.geometry("480x320")
root.resizable(0, 0)

app = Window(root)

root.mainloop()