from tkinter import *
from tkinter import ttk
from tkinter import font
import time
import datetime

def quit(*args):
    root.destroy()

def clock_time():
    time=datetime.datetime.now()
    time=(time.strftime("%H:%M:%S"))

    txt.set(time)
    root.after(1000,clock_time)

root = Tk()
root.attributes("-fullscreen", True)
root.configure(background="black")  #complete background
root.bind("x",quit)
root.after(1000,clock_time)
fnt=font.Font(family="Helvetica", size=120, weight="bold")
txt = StringVar()    
lbl = ttk.Label(root,textvariable=txt,font=fnt,foreground="white",background="black")  #background of the clock
lbl.place(relx=0.5, rely=0.5, anchor=CENTER)
root.mainloop()
