Are there any rules about referees' hairstyles in the World Cup?

No, but a referee represents not only himself, but also his motherland, so the hairstyle should be solemn and generous, and it is best to lead their hairstyle to the country. No, but they represent the image of China. And the situation in Corina mentioned upstairs. Of course, national leaders are bald, hehe!

I hope my sincere answer can be adopted by the landlord.