Just look at Selena Gomez's latest transformation: The team at Nine Zero One salon maintained her dark roots for an edgier effect against her new platinum hair. Of course, leave it to Instagram to take this trend to the next level. First there was glitter roots, but now it's all about vibrant colour. Often referred to as "rainbow roots" or "shadow roots," this new take on the look might not be nearly as practical as Gomez's 'do, but boy is it so damn cool.