带有级别选择的Pygame按钮错误

import pygame

# 初始化Pygame
pygame.init()

# 设置屏幕尺寸
screen_width = 800
screen_height = 600
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption("Level Select Button")

# 定义按钮属性
button_width = 200
button_height = 50
button_x = (screen_width - button_width) // 2
button_y = (screen_height - button_height) // 2
button_rect = pygame.Rect(button_x, button_y, button_width, button_height)

# 定义按钮颜色
button_color = (255, 0, 0)
button_hover_color = (0, 255, 0)

# 定义按钮文本
font = pygame.font.Font(None, 36)
button_text = font.render("Select Level", True, (255, 255, 255))
button_text_rect = button_text.get_rect(center=button_rect.center)

# 游戏主循环
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:  # 左键点击
                if button_rect.collidepoint(event.pos):
                    # 执行级别选择逻辑
                    print("Level selected!")

    # 绘制按钮
    pygame.draw.rect(screen, button_color, button_rect)
    if button_rect.collidepoint(pygame.mouse.get_pos()):
        pygame.draw.rect(screen, button_hover_color, button_rect)
    screen.blit(button_text, button_text_rect)

    # 更新屏幕显示
    pygame.display.flip()

# 退出游戏
pygame.quit()