Though slightly reluctant, Nellor chose to undergo a "makeover" earlier this winter with Dockers, the company that coined the term "business-casual" in 1986 when its leaders saw a khaki-colored middle- fashion ground between blue jeans and dress pants.

When Dockers brought its StyleWork trailer to Portland during a 10- city tour, makeovers were part of its biz-casual consciousness- raising and promotion.

Originally known for its khakis, but now peddling both men's and women's casual-clothes lines in different price ranges, Dockers dressed Nellor in updated, slightly flared flat-front black pants, with a touch of stretch, as well as chunky boots, a fuchsia pullover sweater with a drawcord, and a fax-fur-trimmed parka.

"I wouldn't wear this to court, Nellor said in her new outfit. "But I would to the office."

Like many working women and men who have the option of dressing down, Nellor goes for "comfort with some style. I try to keep updated, but it's a struggle."

Business-casual is not the simplest dress equation to work out. Casual to one office is messy to another. Clients' expectations vary, and regional differences abound. East Coast professionals tend to dress up more than West Coast counterparts. Urban offices are often more formal than suburban ones.

Nellor says her colleagues dress in more relaxed styles than in more formal older days, but we "need to maintain our professionalism."

And that's the trick, fashion experts acknowledge: not looking like a loser in a looser environment.

"Women have a valid concern about what's appropriate to wear in the workplace," San Francisco-based Dockers marketing manager Kelly Moore said during her Northwest visit.

On the other hand, men have their own set of clothing hurdles.

"They often have to start from the ground up to acquire and hone a casual wardrobe for work," Moore said. "Golf shirts and khakis aren't the only choices."

To further complicate dressing well for every occasion, Moore says "we're trending toward one wardrobe. People are looking for versatile separates that go from day to night and mix and match."

Dressing for an informal workplace atmosphere has as many don'ts as dos, but the bottom line is to "dress for your work environment and body type," says Glamour magazine stylist Lauren Oberman, who helped Nellor choose her makeover wardrobe.

Unsafe bets include clothes that are too tight, too sheer, or "too sleeveless," Moore and Oberman agree. A close-to-the-body silhouette is fine, just not one that shows flesh overflowing.

"You want to look comfortable but professional," Oberman says.

Fail-safe styles

Fail-safe looks this year for women include well-made separates instead of tailored suits; khakis with a blazer and a crisp white shirt; colors and shades such as as olive, red, blue-gray, heathers; and fun accessories. Even with the lighter attitude toward a work uniform, "don't go too crazy with patterns," says Moore.

Casual staples include sweater sets, flat shoes and even a long flowing skirt, Moore says. "Keep it comfortable but don't wear anything that makes anyone else uncomfortable."

Advice for men

For men, Dockers' Moore likes casual khakis and slacks as well as collared shirts or polos. She gives a pass to a single-pocket T- shirt with a micro-sueded finish in heathered tones. No sandals, no sneakers and no athletic wear. A belt is as essential as a selection of "well-pressed casual separates."

She dismisses tropical shirts, rumpled permanent-press shirts, indicating a "I-can-get-by-with-as-little-as-I-can attitude" and rugged good-looks flannel or wool shirts, which she calls "professionally repelling."

The wrong tie is the worst mistake guys make any day. The tip of a tie must hit the top of belt buckles, she says, and if they don't, go to one of those big and tall shops and purchase longer styles.

Men, she says, shouldn't wear jeans in the workplace.

What about leather? Glamour's Oberman and Dockers' Moore say the material remains hot for the cold-weather season, as do slightly stretchy fabrics. "They can go from work to a cocktail party," Moore says.

Business-casual may be a difficult concept to carry out because it combines "appropriateness" with style, two concepts subject to individualistic interpretations.

Confused? You can always go back to the suit.