Kylie Jenner celebrated her 21st birthday last night, marking the last legal shift into adulthood for the main Kardashian family members. (At 21, Jenner is the youngest of the original cast. Next up: Mason Disick!) Her theme was: pink stoplight party with a ball pit. All her sisters attended (even Caitlyn Jenner came!), each in a glittery bubblegum-colored dress, and the cocktails came in cups with "stoplight" designations. For those who haven't attended a stoplight party: They are meant to encourage hooking up and/or dating at the party. Attendees sometimes wear certain colors to determine their respective relationship statuses. Green = single, yellow = unsure, and red = taken — the idea being that people will see the designated color and decide how to make a move from there. At Jenner's party, cocktails came in stoplight colors — per Kim Kardashian's generous Instagram story light night — pink = taken, yellow = single "AF," and green = it's complicated.
Ahead, all the best moments from Jenner's hot pink birthday bash.