One of the things about Power Girl is that she seldom has what you would could call a “good” costume. For instance, the boob window on her more typical duds really is kinda silly.
This particular outfit, worn during her Justice League days, is on the cusp. Why I think that I can’t explain. Maybe it’s the neck line. That looks ridamndiculuce. The yellow/white color scheme doesn’t do a lot for me, but it’s growing on me.
Anyways, Power Girl. In a costume we haven’t seen her in before (at least not on this site.)