Well, in the dinosaur days when I was in school, girls were not allowed to wear slacks unless the offical temperature at 6am was 32 degrees or below. Jeans were forbidden under any circumstances for both boys and girls. This was pretty common in public schools in N. Fla. Boys hair couldn’t touch the ears or shirt collar (and your shirt had to have a collar, no t-shirts allowed). Those were the days!!
Dress professionally. That was the rule. I wouldn’t have a problem with Fox News dress code in school.