import pygame
import random

WIDTH = 500
HEIGHT = 500
FPS = 60

WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
running = True
size = 20
while running:
    screen.fill(WHITE)
    for event in pygame.event.get():
        
     if event.type == pygame.QUIT:
            running = False
     if event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:
             size += 5
    font = pygame.font.Font(None, size)
    img = font.render("Hello world", True, BLUE)
    screen.blit(img, (50,250))
    pygame.display.update()

pygame.quit()