Candyland - GOG Sativa

you can exagerrate it, if you want, with temps below 68F at night. if avoiding this stops the color-change, you know it's more environmental but can be genetics too. can exacerbate the displayed trait, if you want too. When it starts reflecting blue and red light (to create a purple color), it's absorbin less PAR. My 2 cents is to not exagerrate the effect, and if genetic enjoy the pretty colors, but this trait likely negatively impacts photosynthesis. i'm not a fan of it, but meh, small potatoes from what i can tell. (limited effect)

Genetics my dear Watson....Granddaddy Purple (or GDP) is a famous indica cross of Mendo Purps, Skunk, and Afghanistan. This California staple inherits a complex grape and berry aroma from its Mendo Purps and Afghanistan parent, while Skunk passes on its oversized, compact bud structure. GDP flowers bloom in shades of deep purple

@NaturesPace purple leaaves can come from cold night time temps nutrient deficiencies or in Your case this is purely from genetics and this particular phenotype is showing its beautiful coloration some breeders will actively select these phenotypes so that future generations will also exhibit similar coloration