Designers have said goodbye to feminine flounces, neon colors and sparkly accents.

Marking the end of a fashion cycle that debuted with the new millennium and reflected the optimism of a once-booming economy, fashion houses have closed the door on boho skirts, tangerine tank tops and strappy sandals. Now, muted gray, navy, burgundy and black are dominating the fall color palette in a fashion tone-down that started last year and has shifted into overdrive. Designers are also featuring military styling, towering platform boots and '80s-flashbacks -- multiple layers such as cocoon tops and tunics paired with skinny pants and leggings.

"This is the biggest change that we've seen for a good six to seven years," says Robert Burke, a veteran retail fashion director who now heads a luxury goods consulting firm in New York.

But the collections are anything but consistent, and they're posing a challenge for retailers putting together their fall offerings. That's because the fashion sea change -- both the magnitude of its shift and the breadth of new ideas -- comes at a time when women are more independent when it comes to following the latest fashion dictates, and more likely to personalize their wardrobes by mixing in styles from past seasons. So stores are stepping up their efforts to educate shoppers about the new styles and how they can fold the clothes into their wardrobes.

Multiple themes emerged when big designers unveiled their fall lines earlier this year in Paris, Milan and New York. Last fall's circle skirts have given way to new silhouettes -- including Stella McCartney's thigh-high shift sweater dresses over tights and Donna Karan's cocoon coats and full tops over skinny jeans and leggings. Designers are taking footwear to new extremes. On Balenciaga's Paris runway, models clad in short coats teetered on platform heels that towered to seven inches. Also giving store buyers whiplash: breakaway looks including high-waisted, full-legged pants, bold plaids, brocade fabrics and ballerina flats.

But the unifying big idea is the layered look. On the runway, YSL, Gucci and Prada all swaddled their models in voluminous coats, scarves and tunic sweaters. In an updated "grunge" collection in somber hues, Marc Jacobs dressed models in as many as 10 pieces at once, including dresses over skinny pants and leggings, accessorized with cashmere scarves, oversize newsboy hats, slouchy handbags and heavy, clodhopper ankle boots.

Even the fashion cognoscenti say they were baffled by the range of choices on the runways in February. "Designers were playing with a lot of things," says Julie Gilhart, women's fashion director of Barneys New York. "If I were a consumer I would be totally confused -- the options include layering and minimal and something in between." Adds Michael Fink, women's fashion director at Saks: "It took the shows in all three cities for my eye to adjust."

Retailers are pulling out all the stops to educate even their most fashion-forward shoppers. In its fall "Want It!" ad campaign, Saks Fifth Avenue is showcasing what it says are the fall essentials -- knits, narrow pant suits, skinny jeans and flat boots. Chains such as Ann Taylor, Kohl's, J.C. Penney and H&M are ramping up their fashion advertising and mailing out "look books" to repeat customers. Kohl's is also touting the layered look on a wardrobe-planning Web site that the company debuted in the spring called Transformationnation.com, where shoppers can experiment with combinations of tops, bottoms and accessories.

And this season, Penney's more than doubled the number of mannequins and dress forms in its stores so it could outfit them head-to-toe in the new layered looks. "For the average person, to see two or three pieces put together and accessorized will help," says Liz Sweney, its executive vice president of women's apparel.

Barneys New York has cherry-picked the collections. "If a woman wants that runway look, layering is really hard to do. You have to think about color, weights and proportions," says Barneys' Ms. Gilhart, who adds that many women shop for a piece at a time, rather than for full outfits. As a result, she says, the store is stocking tops, pants, jackets, scarves and coats it says will work alone as well. "Most women aren't buying every layer."

That would include Christina Smedley. Typical of the new generation of fashion consumers, the 38-year-old marketing executive says she's adapting the looks to her personal style. While she loves the idea of layers -- she just bought a sweater coat, two pairs of platform boots and skinny pants in gray wool -- she doesn't plan to toss out everything in her closet. "I'm not going head-to-toe with the new styles," says Ms. Smedley, who splits her time between Atlanta and New York.

Despite the challenges of winning over consumers, apparel marketers and researchers are optimistic about the prospects for fall collections. For one thing, high-fashion trends are being more quickly accepted by a growing number of mainstream women, who now routinely see runway images online just hours after designers take their bows. During New York Fashion Week last September, for example, Style.com tallied some 399,000 unique visitors to its fashion-show Web pages alone. And these women start their fall shopping as early as May, when precollections hit the sales floors. So far, retailers say all of the fall categories are selling -- the skinny jeans, sweater dresses, the full tops, even the extreme boots.

Women's apparel sales in the U.S. are projected to climb 3 percent to 5 percent in 2006, up from $101 billion from 2005, says Kurt Salmon Associates, a retail consultancy. "This really is a new fashion cycle -- a dramatic shift that bodes well for growth across the industry, because the new shapes force women to buy a number of pieces to update their wardrobes," says Kimberly Roffey, a strategist at Kurt Salmon. In 2004, the peak of the last fashion cycle, women's apparel sales grew about 5 percent from the previous year.

The easiest sell may come from all of the '80s references -- leggings, tunic tops, platform shoes -- that will be familiar to women who wore them the first time around. But some industry experts say the new styles may lack the oomph to spur impulse purchases. An even thornier proposition, they say, will be persuading women to part with the colorful frills and jazzy accents that have sold so well for so long. "The most popular color is gray, which is serious and conservative and certainly no fun," says David Wolfe, creative director of Doneger Group, a New York retail consultant. He summed up the runway shows as "deadly serious and intellectual."

Here is a closer look at some of the fashions showing up in stores, with versions at all ends of the price spectrum -- plus, in some cases, countertrends that shoppers may also see:

Platforms Rising

RUNWAY: Balenciaga's short platform boots -- with seven-inch heels and a $1,910 price tag.

REALITY: Chunky boots and pumps, with three- to four-inch heels.

FLIP SIDE: Flat boots make a comeback alongside best-selling ballerina flats.

This fall's biggest fashion news comes from thick platform pumps and ankle boots, designed to balance the proportions of the new top-heavy silhouette. At Bergdorf Goodman, extreme styles -- with heels at five or six inches -- have been moving briskly, says Linda Fargo, the store's women's fashion director.

But most of the new footwear will have heels under four inches, retailers say. Footwear giant Nine West's new platform styles -- including the "Francisco," a $75 patent-leather pump with a thick, 3 1/2-inch heel -- will make up about 15 percent of its line. Upscale shoe designer Stuart Weitzman says platforms will comprise about 40 percent of his line, up from 15 percent last year. Weitzman styles include "Chilly," a suede platform ankle boot trimmed in shearling with a 2 1/4-inch stacked heel ($350) and "Expump," a peep-toe pump with a 3 1/4-inch heel ($280).

To accent the muted fabrics, designers are pushing shoes (and handbags) with flashes of red and red patent leather. Says Ken Downing, women's fashion director of Neiman Marcus: "Under that dark color palette, nothing will make you happier than shoes in bright tomato to deep mahogany."

While women may be having flashbacks to 1970s platform shoes -- sidewalk sprawls, turned ankles -- retailers say this time will be different, thanks to advances in technology. "Manufacturing the heel and separate platform is more precise than in the past, creating a sturdiness, so that your foot rocks -- instead of the shuffling that occurred in the 1970s," says Heather Pech, chief executive of Nine West stores. The thick platforms are also lighter and more flexible than the hard, heavy plastic soles of the past, says Stuart Weitzman.

The Skinny on Pants

RUNWAY: Skin-tight pants and jeans.
REALITY: Drainpipe pants -- and a new take on the matching pant suit.
FLIP SIDE: Wide-legged pants are also fashion news, and flared jeans -- sans embellishment -- are still in stock.

Skinny jeans became bestsellers this past summer, inspiring stores to stock a broad array of straight-legged pants for fall -- with designers including Michael Kors, Donna Karan, Prada, Chanel and YSL showing them, often under skirts or dresses. Though premium designer jeans have hogged the headlines in recent seasons, Penney's Arizona brand ($24.99) was named best-fitting skinny jean by Seventeen magazine in its September issue. Ann Taylor Loft is selling $54 straight-legged jeans with a cut that's a bit more comfortable and forgiving.

At Olive and Bette's, a New York specialty boutique chain that also sells online, only about 20 percent of its jeans will be straight-legged compared to 80 percent with a boot cut. "The truth is you have to be a size 2 to 4 to really pull that off," says Stacy Pecor, the store's owner. "Some of the jeans are so straight it's hard to get your pants over your leg."

For working women, the matching pantsuit returns for the first time in nearly a decade from retailers including Saks Fifth Avenue and Neiman Marcus. The new versions -- often in black or gray -- have tight tapered pants and fitted cropped jackets with wide portrait necklines and three-quarter length sleeves. Often worn without a blouse and accessorized with pumps, they're sleeker than the boxy women's business uniform of the '80s.

Swaddled in Layers

RUNWAY: Voluminous coats, knit dresses, scarves and tunic sweaters and miniskirts over leggings.
REALITY: Most women will stop with a single layer. Expect to see this uniform: black-and-gray striped tunic sweater with a wide belt and black tights.
FLIP SIDE: Unbulky military-style coats.

The "mushroom silhouette" -- full at the top and narrow at the bottom -- is the foundation for fall dressing. Loose, egg-shaped tops should appeal to boomers in particular, as the forgiving silhouette hides waistlines and hips.

Ann Taylor Loft has zeroed in on kimono- and dolman-sleeved sweaters at $49. At Kohl's, sales of oversize tunics have been "outstanding," says Peggy Eskenaze, executive vice president of product development. Penney's introduced a new brand called a.n.a., which features big shirts, inspired from runway looks.

In the same vein: sweater dresses and jersey dresses that women can wear over leggings or slim jeans. Fast-fashion specialist H&M is showing dresses in a variety of shapes including shifts, in camel, beige, navy, red and browns, priced from $40 to $70.

According to Nina Stotler, trend director of fashion-trend consultancy Peclers Paris, retailers have been banking particularly on jersey dresses. "Their soft plumpness is a trademark style that is so Los Angeles, like updated T-shirt dressing," says Ms. Stotler. Many women will pair sweater dresses with sweater coats, a look Bloomingdale's expects to be popular this fall. "Jersey dresses are already blowing out of the store and we haven't seen sweater coats in a long time -- they work well" as transitional coats and in warmer climates, says Frank Doroff, a senior executive vice president at Bloomingdale's.

Score It or Store It

Bye-bye boho and feminine frills. Here is what's coming in and going out this fall:

SCORE IT: Tunic sweaters, full blouses with dolman sleeves belted at the waist.
STORE IT: Turtleneck cashmere sweaters in rainbow shades.

SCORE IT: Thick platform shoes and boots.
STORE IT: Slingback stilettos and cowboy boots.

SCORE IT: Skinny jeans in dark denim, black leggings and opaque tights.
STORE IT: Low-rise boot-cut jeans, sequined jeans.

SCORE IT: Above-the-knee A-line skirts, lean dresses with belts at the waist.
STORE IT: Ethnic, tiered bohemian skirts with low-slung belts.

SCORE IT: Minimalist-look jewelry -- flat and sleek in gold or silver.
STORE IT: Chandelier earrings, flashy diamond or crystal necklaces.

SCORE IT: Military-style coats with buttons, cocoon-shaped coats.
STORE IT: Straight coats in colorful embroidered fabrics.

SCORE IT: Black or "money-green" handbags with gold trim; red bags to accent dark clothes.
STORE IT: Handbags with outside pockets, buckles and geegaws.