Actually, when they were covering up her feet, I figured she MIGHT be barefoot. Because feet are insanely hard to draw, and so it would make sense to cut them out like that. (There is a ridiculous amount of panels were their feet are obscured for one reason or the other.)
Or that, you know, she'd wear flats, as she's obviously wearing something... but no, no, extremely high heels for her. I'd say they're about 3 inches of heel even. Maybe to do with her 'I twist men around my little finger' personality?