The earliest Klansmen after the Civil War didn’t really have a standard outfit but they did wear masks sometimes. The white robes and pointed mask was literally invented by the MOVIE “The Birth of a Nation” (technically the book first but movie was more popular) that put the Klan in those robes because they thought it made them look cool. Then real Klan Members started doing because they thought it looked cool in the movie. The Klan would actually go to movie showings in those robes like fucking harry Potter LARPers lol