In her role as the other side of Tony’s coin, Pepper dresses the way the head of Stark Industries should be dressing, even before she’s promoted to CEO. Thanks to the boardroom uniform of two-piece suits it’s a lot easier for men to look businesslike than women, but Pepper’s an expert. Tony only seems to wear a suit when Pepper picks one out for him, otherwise he’d be perfectly happy to show up at press conferences in the same Styx t-shirt he’d been wearing for the last fifteen hours in the lab. Pepper, on the other hand, is a very careful dresser and has a distinctive style. With the exception of formal/party outfits, everything we see her wear is either black, grey or white, and all of it is very closely tailored. In fact, Pepper’s wardrobe is quite similar to what Gwyneth Paltrow wears in real life, which must have been helpful for branding purposes while promoting the films. I recall that during the publicity tour for at least one of the Iron Man movies she wore 5-inch heels for all her interviews and TV appearances, still visually in-character as Pepper.