I went to high school in the late 70s and was lucky enough to see a few girl fights. Unfortunately, back then girls wore jeans pretty much exclusively. Bare legs and panties were only viewable to boyfriends. The girls weren't that conservative, it was just the style.
My wife however is from the Philippines and there students wear uniforms. White shirts and and school color pants for boys, white shirts and pleated school color skirts for girls. My wife's school color was maroon so she wore the shortest skirt she could get away with just like the other girls did. She would wear a longer skirt leaving home because her dad would yell at her if he saw her leaving in a short skirt. The girls would get to school and all crowd into the bathroom to change into shorter skirts then change back before going home. The Philippines was, and kind of still is, a conservative country.
She had several fights during her school years. If she thought she might fight that day she wore shorts under her skirt since she would likely be flashing anybody watching while rolling on the ground punching, scratching, kicking and pulling hair. She always fought across the street from her school at a park since the girls would get in trouble for fighting on school grounds. She won most of the time but pretty much always lost some buttons from her blouse so her mom would chew her out when she got home.