Swift's fourth studio album, Red (2012), experiments with various pop, rock, and electronic genres. It included the top-five singles "We Are Never Ever Getting Back Together", her first Billboard Hot 100 number-one hit, and "I Knew You Were Trouble". With her fifth studio album, 1989 (2014), she announced her full transition to pop. The synth-pop record made Swift the first female solo artist to win the Grammy Award for Album of the Year twice and amassed three Billboard Hot 100 number-one hits—"Shake It Off", "Blank Space", and "Bad Blood". She extended the electronic-pop sound on her next two studio albums: Reputation (2017), which incorporates elements of hip hop and featured the Billboard Hot 100 number-one single "Look What You Made Me Do", and Lover (2019), which was the world's best-selling studio album of 2019. Swift's indie folk and alternative rock eighth studio album, Folklore (2020), and its lead single, "Cardigan", made her the first act to debut atop both the Billboard 200 and Hot 100 simultaneously.