Summer is slowly coming to a close but Michael Costello kept summer romance alive with his Spring/Summer 2017 collection. Risqué high slits, beautiful floral details and deep purple tones took the theme, "Midnight in a Secret Garden" to a whole new level of sexy. Here are our favorite looks from the runway: Crowned the best look of the show, this purple gown with floral embellishments, daring slits, topped with an efflorescent crown is the epitome of a botanical fantasy. The…