MILAN — Giorgio Armani is in a soft, slouchy mood for spring, and he expressed it in the strong collection he showed on Monday in such looks as loose sweaters over wide pants and jackets with gentler new lapels. These fluid variations on his classics were clearly meant to offset the concrete of his monumental new headquarters, where he showed. Here, a shoulder-baring top and pants. For more on the season, see pages 4 to 7.