It makes sense that a group named Color Outside the Lines (aka CORTIS) would lean into a strong chromatic theme. On their second EP, following the five-member K-pop squad’s self-titled debut in 2025, James, Juhoon, Martin, Seonghyeon, and Keonho broadly sort subjects into two categories: red for disapproval and green for rampant enthusiasm. The concept is most prominent on “REDRED,” a dance-rock track bursting with energy. (According to the teen idols, playing it safe and faking being cool is red, while hopping the wall is green.) But it also plays a prominent role on the album ender “Blue Lips,” a moody bedroom-pop track about the “bitter and sweet” of chasing a big dream. Elsewhere on GREENGREEN, the pursuit of self-description takes broader, more complex forms. On “TNT,” the members reminisce about their start at 16 as “five brats in a room every night/At the studio PC waking our DNA.” Their preferred label as a “creator crew” who take part in all aspects of their production takes center stage on “YOUNGCREATORCREW.”