MILAN — In a runway season full of sexpots, the idea of well-brought-up young girls seems decidedly refreshing. And that was just the effect of the Miu Miu collection Miuccia Prada showed here on Tuesday. Prada’s muse was a charming coed who happens to have a yen for Hawaiian prints, which turned up in the form of jams, little skirts and cocktail dresses. Her accessories of choice included spectator pumps and plastic leis. Here, a V-neck sweater, top and Hawaiian-print skirt. For more on the shows, see pages 4 to 6. For more on the shows, see pages 4 to 6.