Pygame zero not expanding screen.

Hi, I am coding a pygame zero project. I filled the screen with white, and ran it. I did not get an error message, but when I maximize or manipulate the size pf the output screen, it is no longer whit and it starts glitching. However, my other pygame zero projects on replit do not do this. When I maximise the screen, it acts normal. I am wondering how to solve this.

Link to my code:

My code:

import pgzrun

#defining screen size
WIDTH = 800
HEIGHT = 600

#draw stuff on screen
def draw():
  screen.fill((255, 255, 255))