在display PyGame上矩形不移动

import pygame
pygame.init()

window_width = 800
window_height = 600
window = pygame.display.set_mode((window_width, window_height))

rect_width = 100
rect_height = 50
rect_x = (window_width - rect_width) // 2
rect_y = (window_height - rect_height) // 2

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    window.fill((255, 255, 255))  # 清空窗口
    pygame.draw.rect(window, (0, 0, 255), (rect_x, rect_y, rect_width, rect_height))
    pygame.display.flip()  # 更新窗口显示

pygame.quit()