Black leggings.
I think it’s her legs! Check out the length of the “leggings”. On her right leg the shadow goes to the ankle, on the left leg it stops right below the knee. I increased the brightness on my screen and swear that’s skin we’re seeing. In the interest of full disclosure I wear some strong reading glasses. Your eyes may be the better pair.
I don’t know what photo you are looking at but there are absolutely NO leggings under that skirt - look at the photo beside the helicopter when the wind is blowing her skirt up....
It is shadows. That is unless her black leggings are different lenghts on each leg. LOL