Vintage flapper style has long been a fashion inspiration, especially with the promise of Baz Luhrman’s anachronistic, aesthetically thrilling “Gatsby” adaptation on our heels, but methinks Katy Perry may have taken the trend a bit too literally at last night’s City Of Hope gala. Her long, lacy silk slip is perfectly lovely, but the headpiece and haphazard pearls send the whole thing straight into Halloween costume territory. The silver mules are definitely retro, but not in a good way — they’re more bridge champion than pop star. Also, yin-yang nail art? Where is Katy trying to go with this? I’m confounded.