Python Tkinter color not working, it is the same whether I change the customization with canvas

Question

I apologize in advance for any ignorant mistakes I make, I am still a beginner.

I recently started using tkinter on python, and while I tried using the backround customization in tkinter, It does not change any colors in the backround, the same goes with the frame. below is the code I have written.

import tkinter
import tkinter as tk

class GUI:
    root = tkinter.Tk()
    canvas = tk.Canvas(
        height=700,
        width=700,
        bg="#263D42"
    )
    canvas.config(bg="green")
    canvas.pack()
    root.mainloop()

    frame = tk.Frame(root, bg="white")
    frame.place(relheight=0.8, relwidth=0.8)

I am using M1 MacOS if that information helps, here is a screenshot of the GUI, it is the same when I comment out the color customization in the code.