What program is used to animate Steven Universe?

A friend and I were talking about animation. I assumed most animation was done in Flash, and good looking shows were just particularly well animated flash. As in animating characters frame by frame over reusing the same general animations.

Think 70's era Hanna-Barbera reusing walk animations during filler talking scenes compared to fluidly animated Disney movies.

Wikipedia says Steven Universe traditionally animated, but I can't find with what.

I'm not saying flash sucks, I've seen it used for beautiful things. It just really shows when used poorly. (Teen Titans Go!)