If you stride into your sunny, corner office at daybreak and head home by the light of the moon, Carson Pirie Scott & Co. wants to find a way to fit into your shopping time. In hopes of increasing sales and attracting a new group of more affluent customers, the department store chain gentrified itsflagship downtown store's bargain basement and rechristened it "Corporate Level."

The newly redesigned belowstairs realm is aimed at downtown workers who now can buy clothes, eat lunch, get a haircut, see a broker, do some banking, book a cruise, drop off the drycleaning and visit the cobbler in one efficient trip.

A doorkeeper clad in black piped with silver greets what the store hopes will be the new class of basement shoppers at a separate, street-level entrance. A loudspeaker at the down escalator recites, "Welcome to Corporate Level, the ultimate destination for your career." To enhance the aura of exclusivity and sophistication, salespeople pack Corporate Level purchases in black shopping bags that are emblazoned with metallic silver logos.

The specialty floor is open weekdays from 7:30 a.m. till 7:30 p.m. to jibe with the workaholic schedules of its target customers. Thursday morning at 7:43, for example, a woman from the sales department of a La Salle Street investment firm already had picked out a new leotard for aerobics class. "This is the only time I really have to shop," she said. "I'm usually at work by 7:30." She said she also likes to avail herself of early-morning grooming services: "If I have a meeting and I need my hair cut, I come here."

Women's clothes hang on streamlined, chrome fixtures that catch and hold the brightness of the overhead track lights. "Wardrobe consultants" help uncertain shoppers achieve the confident, pulled-together look they seek.

Down the aisle from the serious stuff are brightly lit cases of restrained, yet fanciful, costume jewelry, bags, belts and scarves. A few steps away, shoe consultant Kim Wilson surveys her wares.

The flow of cock's crow traffic is fairly predictable, she said: "Between 7:30 and 10, before the rest of the store opens, we get a lot of women who got a run in their hose or who broke their shoe on the El." She said she also gets trade from women who decide, between home and the airport, that they can't leave town without "a new pair of fancy pumps."

Corporate Level debuted in two stages. The women's departments and a lunch counter have just passed the one-year mark. The banking and investment services, the barber and the men's clothing sections opened Aug. l5.

So far, the venture "has produced greater sales per square foot than any other area in the State Street store," said Carson Pirie Scott's retail group chief executive officer, Dennis S. Bookshester.

"Corporate Level did $175 per square foot its first year, and our goal is $200 in this coming year," said Financial Vice Chairman Ronald G. Kalish. Those numbers compare with a State Street Carson Pirie Scott store average of $100 per square foot. The average for the corporation's retail stores is $103.

Buoyed by a successful first year, Kalish said there is corporate discussion of opening storefront Corporate Levels in other markets. "Washington might have the right concentration of professional people living downtown," he said. Carson Pirie Scott & Co. already has a presence in the District. It acquired Ridgewell's Inc., a caterer, last year.

Corporate Level for Men will be courting customers who revere and honor the tribal codes of business attire. Such men typically buy their suits at small, intimate specialty stores. The greatest challenge facing the sales staff will be building a customer base, store officials said.

Brooks Bros. Marketing Vice President Ron Brown said that the type of customer who shops at specialty stores "might not credit the Carson Pirie Scott salesman with the same authority he would impute to his Brooks Bros. salesman."

"Some men hate to shop at department stores because they've had bad experiences, but it should be a fun thing for men to do. We coordinate our displays so people will have an idea," clothing consultant Craig Terry said. "It makes it easier. Some men will buy the whole display. I can sell them the total outfit, right down to the shoes and the socks.

Looking sartorially unassailable in a charcoal gray suit, white, medium-point-collar shirt and yellow foulard tie, Terry leaned back on the heels of his cap-toed shoes. "I always wear the best clothing I can get, and that's what I tell the young men. I always ask them what business they're in before I start showing them suits, because you want to look the part."

One of the open secrets of modern life is that signing off on a million-dollar deal is less stressful for many men than buying clothes. "The confidence they have at the office sometimes vanishes when choosing a suit," Carson's Bookshester said. "Male shoppers appear to need more pampering than women, and we intend to give them all the service they can handle."

Around the corner from the men's departments are the financial services stations.

The bank is a branch of United Savings of America, a Chicago-based savings and loan institution. A vice president shuffling papers at her desk said, "If people are here early in the morning to do their banking, or after work, we're going to be here during hours when other banks are not open. It's been quiet so far. Only time will tell."

"This is the second-largest market in the country," said Dorothy Fuller, director of the Chicago Apparel Center. "Sixteen percent of the buying power in the U.S. is within a 300-mile radius of Chicago. Marshall Field's is a Chicago institution, and so is Carson's. Field's has always been the prestige store -- they repaired my grandmother's linen -- and Carson's has been the volume store. There are a lot of changes going on in retailing."

Gutting and revamping what Kalish calls the "down and dirty basement" of the 21-store chain's flagship was a wrenching innovation. Generations of shoppers prospected there for bargains. "It's like they've turned the store upside down," a saleswoman said.