Teste de cores no Tkinter..

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import tkinter as tk

root = tk.Tk()

def gray_label():
    label_text.config(fg = "#FFFF00", bg = "#FFD700")

label_text = tk.Label(root, text = "Texto", fg = "blue",
    font = 'Helvetica 20 italic')

label_text.place(x = '20', y = '20')

checkbox = tk.Checkbutton(root, command = lambda: gray_label())
checkbox.place(x = '20', y = '80')

root.title('Tkinter Cores')
root.resizable(False, False)
root.config(background = 'white')
root.geometry('250x200')
root.eval('tk::PlaceWindow . center')
root.mainloop()