The peripheral benefits of back-to-school fashion choices this fall include attributes like comfort, quality, reliability and beauty -- but a wardrobe's most important function for Twin Cities teens?

Expressing who you are.

"On the first day of school, you have to make an impression," said Liz Doyle, 15, a Minneapolis South High student who was shopping at the Mall of America. Her friend Clio Cullison added, "It kind of defines you."

The annual return from summer break amplifies the Catch-22 confronting teens this fall as much as ever: "Everyone wants to fit in but also stand out," said Joshua Thomas, a Target spokesman.

Girls will do that with a focus on flashy, glitzy takes on old styles, and boys' usual sporty look will pop with bright colors.

Fancy fabrics, patterns

Prints and sparkles. Stripes and polka dots. Lace and patent leather. Many tween and teen girls are going for attention-grabbing styles.

"It's kind of like the live-out-loud season," said Maegan Goers, 18, who was shopping at the Mall of America for her upcoming freshman year at St. Paul College.

Lace tunics or details on sleeve insets are also popular, said Sara Rogers, trend specialist for the Mall of America. Forever 21 carries a lace blazer for $27.80.

And "feathers, feathers, feathers" are showing up in girls' hair and on earrings and necklaces, she said.

Tribal and animal prints, as well as nontraditional stripes and color blocks, are popular for girls, too.

While shopping at the Mall of America, Fardowsa Hassan, 15, and her friend Nadiira Farah said they love the look of cheetah patterns. Hassan slipped on a pair of cheetah-print flats ($15.80) while Farah looked at a blue-and-black animal print scarf ($9.80).

Doyle and Cullison said they, too, like tribal-print shirts and dresses. "They're edgy," Doyle said.

It's all in the sleeve

Minda Sherman, 19, and her friends like Dolman tops, loose-fitting, thin shirts that fall naturally off the shoulder to one side. "But not the one-arm shirts," said Sherman, who's also headed to St. Paul College this fall.

Rogers said Dolman and kimono sleeves, which are both wide and flowy at the armpit, fit better under ponchos or capes, so these are more popular than fitted-sleeve jackets for chillier fall days.

Sherman likes the look of pairing those tops with tight-fitting jeggings (the popular jean-legging) or, better yet, "yoga pants -- with an exclamation point."

Denim reinvention

While denim is a dependable fall necessity, fashion professionals say that this year, teens are creating new twists on the old favorite.

Girls are running to denim in bright colors like red or royal blue, and boys are changing up their jeans, too, choosing gray, black or khaki denim instead of the usual indigo, said Rogers.

Flared jeans are making a comeback for girls. "Skinny jeans are out," said Goers.

Denim from head to toe is the must-try trend this season, said Dean Hacker, vice president of trend and color for Kohl's. "Students can pair a matching denim shirt and shorts for a monochromatic look," or create contrast by pairing light- and dark-washed denim in different pieces, he said.

Blurring lines

Boys and girls are gravitating toward styles that test gender norms in fashion.

Boys are wearing slimmer, tighter-fitting jeans, after seeing them on celebrities like Justin Bieber, Rogers said. "Guys seem to be embracing it."

As for girls, the professional-looking oxford shoes are popping up; the flashy ones are all the rage, like the black patent leather pair that Cullison sought out at Nordstrom Rack ($20.97). "There always seems to be a bit of that borrowed-from-the-boys look," Rogers said.

Popular unisex items include square-framed fashion glasses -- ones that don't actually offer any sight improvement -- what Rogers calls "geek chic" or "smart-y art-y."

Sports all the way

For teen boys, fashion is mostly about sports gear -- whether to demonstrate to others their love of the game or to show off a team they support.

Toe-shoes are big for runners, said Andy Pierson, 17, a senior at Hill-Murray School in Maplewood. The running shoes fit snugly to the wearer's foot, separating each toe for a more natural feel. Finish Line has them in several styles for $59.99.

Matt Bright, 14, of Edgerton, Wis., wears long gym shorts year-round because, "It's not cold," said the tough guy. Target's exclusive brand C-9 by Champion offers sports shorts cheap (as low as $5.58).

Rogers, the trend specialist, said guys are turning to colorful graphic T-shirts, specifically in red, mustard and rust. "The graphics are pop-culture images; it might be an iconic band like the Beatles or inspired by an upcoming movie, like 'Captain America,'" she said.

Jessica Bakeman • 612-673-4401