Slip skirts are this season's perfect alternative to your everyday jeans. Not only do they go with anything, but they're also comfortable and very on-trend this spring. Reminiscent of the '90s, the silk slip is back with a vengeance--and we're here for it. Something about the shiny fabric can transform even a basic t-shirt outfit into a super-chic look, so we feel justified in dubbing it wardrobe staple that belongs in every closet. Color: brown one layer of real silk XS/S/M/L/XL bias cut…