Which is nice. “Kung Fu Panda 3,” in spite of its abundant action—and for all the interspecies mashups, this is as much an action-adventure animated movie as it is a funny-animal animated movie—is a pretty relaxing experience for the adult viewer. The colors are beautiful, the design of the varied realms is ingenious and pleasing, the animation fluid and graceful. This panda doesn’t pander—there are scant, if any, nudging pop-culture references soliciting laughter from knowing grown-ups. “Be the best you you can be” is this movie’s message, and writers Jonathan Aibel & Glenn Berger, and directors Alessandro Carloni & Jennifer Yuh heed their own advice throughout this brisk romp.