I guess I'm going to be the dissenting opinion here because I think you could do much better on the borders. Maybe it's my display but the borders look brown to me. I would prefer something more along the color lines of the light green squares for the inner border. With that the outer border might work better. Or something with more reddish coloring for the outer. These borders are adequate but I think it would " pop " more with different values ( even more than different colors) in the borders.
Just my two cents. Interested in what others say.