When considering lighting needs for your residential steam shower application, you must consider all the uses for this environment and implement accordingly. Things like cleaning the shower, shaving, and bathing the kids/pets would be rather difficult in a poorly lit environment. On the other hand, having stadium lighting during a steam shower is not exactly relaxing.
A general rule of thumb is to provide 60 watts of lighting for each 20 square foot area of the steam shower. For a 7’ x 10’ environment, this would call for (4) 60-watt fixtures. These can be switched in various fashions to provide a full range of lighting options.
Read more about steam shower lighting at http://www.steamsaunabath.com/design/all-about-steam-rooms-and-steam-shower-design-vapor-proof-lighting.htm#lights
Read more about mood lighting at http://www.steamsaunabath.com/design/all-about-steam-rooms-and-steam-shower-design-chroma-therapy-and-mood-lighting.htm#chroma