This is actually a mani I posted to my Instagram a few weeks ago, but am posting again here so I can test out the watermarking app I just downloaded.
ANYWAY, if you want to recreate this, I used Avon Nailwear Pro+ in Sweet Pea Dream as my base color. Then I used Nailwear Pro+ in Starry Sky on an angle from about mid nail down. I finished using nail art enamel in Black Drama to make a black line where the two other colors met.