I think you are talking about what happens in Part 2, Chapter 8, not Chapter 7.  In this chapter, Winston and Julia go to O'Brien's apartment.  This is not the Inner Party's headquarters, but it is the home of an Inner Party member.

The environment described here is the only environment in the novel that is in any way luxurious or elegant.  It is the only one that seems to be designed for comfort.  Winston notes that it even has the only clean halls he has ever seen.  O'Brien even has wine, which Winston and Julia have never even seen before.

Every other place that is described in the book is cramped and crowded, usually smelly, and certainly not luxurious.