By Lauren Zumbach Beauty retailer Sephora opened its 400th location, on Chicago's Magnificent Mile, on Friday. The location is one of the first where customers can get a look at Sephora's new Beauty TIP Workshop — named after the company's "teach, inspire, play" motto — with more high-tech touches and space for classes and experimenting with products. Sephora Americas President and CEO Calvin McDonald talked about the new store look and why Sephora is "bullish on brick-and-mortar retail" in a…