The designer behind Hello Kitty is stepping down after 46 years, during which time she oversaw the feline character achieving world recognition. Yuko Yamaguchi took over design duties for the character — who isn't actually a cat, but a little girl from London — in 1980, five years after she first launched. Hello Kitty was immediately popular in Japan, but over Yamaguchi's four-decade tenure has become one of the most lucrative franchises in the world. Sanrio, the firm behind Hello Kitty, said