The wilaya (city hall) opposite was constructed in a neo-Moroccan-meets-art deco style, but step inside and the architecture takes an Arab-Andalusian feel where, from under the arches, local government officials’ offices overlook a central patio and fountain. Add to this a streamliner interior, monumental staircase, touches of Venetian style on the exterior and a modernist clock tower, and you have a building that is testament to the city’s innovative architectural heritage
MW defines streamliner as:
one that is streamlined; especially : a streamlined train
And defines streamlined as:
1
a : contoured to reduce resistance to motion through a fluid (such as air)
b : stripped of nonessentials : compact
c : effectively integrated : organized
2: having flowing lines
3 : brought up to date : modernized
So does streamliner interior mean an interior shaped in such a way to reduce air resistance, or does it mean the sense b, or c or maybe even 3?