What is the ruling on a girl who has not reached puberty wearing pants and revealing clothing?

There is no explicit evidence regarding the 'awrah (intimate parts) of a young boy or girl. However, most jurists hold the view that if a girl reaches the age of desire, her 'awrah is the same as that of an adult woman. If she has not reached that age, then there is leniency regarding her hijab (definition). It is obligatory to accustom a girl to modest and covering attire from a young age, so that she does not become accustomed to revealing clothing, because accustoming children to short clothes might make it easy for them to expose their 'awrah in the future.