original
The original interior of the hotel has been replaced.

dark, dim, gloomy, shadowy
roomy, spacious
luxurious, plush

decorate, design
redecorate, renovate

decorator, designer

in the interior
There is ample space in the interior of the car.

Interior is used with these nouns:
courtyard, decoration, design, designer, finish, fitting, layout, lighting, minister, monologue, paint, space, surface, volume, wall, woodwork