Black-Tie
Simply put, black-tie attire is typically reserved for formal evening events. Guests are required to choose floor-length gowns and tuxedos (and nice suits) when attending this type of celebration.
All colors are fair game except for white, off-white, or anything else that's even close to white. Apart from that, the only hue you might want to avoid is the color the bride has chosen for her bridesmaid dresses. Pastel hues are lovely to wear.
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