Zara Larsson, the popstar who rose to fame by winning a Swedish talent show at the young age of 10, is now in the strongest stretch of her career. The Swedish singer won two American Music Awards (AMAs) in May, and "Lush Life," released a decade ago, returned to the Billboard Hot 100 after a fan-dance video went viral. Her fifth album, "Midnight Sun," arrived last year to strong listener reviews and has taken her around the world on a tour of the same name. On Sunday, that tour reached Myunghwa Live Hall in western Seoul for her first-ever headline show in Korea. She had visited only once before, for the 2017 Asia Song Festival. Demand was high enough that a second night was added, and both sold out. For an artist of her current profile, Myunghwa Live Hall, a performance venue with a capacity of about 1,600, is a surprisingly small room, but nobody in it on Sunday night seemed to mind. Many in the crowd were fully glittered and glammed up, flowers in their hair and all, dressed as if the night was a party of their own. Larsson opened the 7:30 p.m. show with the title track, "Midnight Sun