With more than $1.3 billion at the global box office, “Black Panther” was one of the year’s biggest hits. Though some people expected just another superhero film, the project turned out to be much deeper and more complex than that. Many called it a social turning point because it was the first blockbuster with a mostly black cast. And below the line, the film’s three top department heads were women. Director and co-scripter Ryan Coogler talked about his team and the challenges members faced in preparing the critically acclaimed movie.