Bottom has 6 huge rooms.
Large Chandelier and lamps throughout main entrance room
Spiral lamps in the 2 adjoining rooms
Dual chandeliers and large area glowstone floors covered in white carpet in the side rooms
Added random plants throughout lower floors only

UP
Each floor has a different color carpeting
Each floor has flush lighting in ceilings.
Full glass elevator shaft from bottom to top, with the exception of the final 3 floors (VIP type rooms) which have their own separate ways of getting up.
 
 Structure is 111 blocks wide (looking at it from the front) 68 blocks long (depth from front to back) 111 blocks tall