Need advice for not-white grout for tile floor and walls. The floor tile is matte white with glossy light gray accents (http://tinyurl.com/yazxs2j2). The wall is a combination of large and small formats of a glossy white with gray marbling (http://tinyurl.com/y886jsxa). I assume a light gray grout for the walls, but suggestions and specific color names are welcome. For the floor, I don't want the glossy gray accents to exactly (or attempt to) match the grout but I'm not sure how much darker to go. Feel free to weigh in about whether the same grout color should be used on walls and floor. FWIW, the countertop will probably be a light-to-medium gray, non-sparkly quartz. Thanks!