How to change the background color in Pygame?

Question

I am creating a game using pygame and I am using rapidtables.com for this work but my game window is still not showing the required color. (It's showing but only when I close my game window). Here is my code-

#Space Invaders
from turtle import Screen, screensize
import pygame

#Intialize the game
pygame.init()  

#formation of screen
screen = pygame.display.set_mode((800,600))

#Title 
pygame.display.set_caption("Space Invaders")

#Game loop
done = False  
  
while not done:  
    for event in pygame.event.get():  
        if event.type == pygame.QUIT:  
            done = True  
    pygame.display.flip()  

#RGB, Red, Green and blue
screen.fill((255, 0, 0))
pygame.display.update()