Here is the first of Keiko's outfits. Simply the girl's uniform for students at Ohtori Academy. We see her in this ensemble almost all the time throughout Shoujo Kakumei Utena.

Here we see Keiko's dueling uniform. Just like almost all the Black Rose duelists's outfits, hers has 2 rows of buttons, and very dark colors. She wears this in episode 21, while dueling with Utena.

More to come soon!