Don't be fooled by the first two singles and the candy-covered "California Gurls" video: Katy Perry's second album, "Teenage Dream," is not all sugar and rainbows. Two years after "One of the Boys," the hit-loaded debut that made her a star, Perry is tempering all that innocent light with a bit of more experienced dark. Tracks like the delectable "Gurls," "The One That Got Away" and "Teenage Dream" have more texture than anything on "Boys," conjuring the high school fairytale promised by the album title. But "E.T.," "Who Am I Living For?" and "Circle the Drain" get heavier sonically and lyrically, with a boom-boom-pow electro punch and Perry discussing more toxic relationships. With a co-writing credit on every track, she name-checks Biblical heroine Esther and classic novel "Of Mice and Men" and uses pearls and pyramids as metaphors. But this new depth shouldn't surprise; for all the pomp and watermelon costumes, Perry is primarily a smart and personal pop songwriter. And "Teenage Dream" shows-in carefully selected spots-that she's ready to grow up.