When did MLB start banning teams from wearing white pants on the road (as I've heard a few times over the years is the case)? The Cubs did the colored jersey/white pants thing through 1989, and some others (especially the A's) used to always wear the same type of white pants at home and on the road.
Also, for what it's worth, watching the game last night, I asked my wife, who's very much into fashion and properly-matched outfits (I always defer to her when going clothing shopping), what she thought of the powder blue Phillies against the orange/grey Astros. Interestingly, she said the only thing she'd fix is having the Astros in navy pants.