INSPIRATION Very Neutral: No color It will create space.   Neutral Travertine flooring/ Porcelain For contrast to match the master bedroom carpet, use a light gray slate.  This is a sample of a 24 x 24 from Floors and Decor.  Limited qty and may not be available in Pittsburgh But I like the veining.  Floor and Decor  Bethel Park.  3000 Oxford Drive, Bethel Park, PA 15102 MATCHING SHOWER AI messed up the colors - but you get the idea.  I am not a big fan of marble unless it looks real. It's been so overused, and the cheap imitations are now dated.  But this is a classic look with a new twist.  Next, I asked it to add black handles and a black shower surround.  Your shower has 3 sides.  This example only has two.   Maybe use the pencil tile in the center and the white tone on the sides.  You can keep it simple and use a nice! subway tile and use a marble hexagon on the shower floor.