Playful leaf-imprint curtains, smudged green walls and a custom-designed rug impart child-like whimsy in Jordan Passon's Seattle living room. "It's my favorite room," she says. "The colors are so organic."

LOTS OF COUPLES work out a simply equitable arrangement for household tasks: One handles the outside, one handles the inside.

Cary and Jennifer Lang have taken that concept one step further.

He builds the houses; she decorates them.

Their arrangement has paid off for the homes they sell as Cary Lang Construction, and on a more personal joint project, a multi-level stucco house set on nearly three-quarters of an acre in the Adelaide section of Federal Way, overlooking Puget Sound and Maury Island.

Together the Langs have created a striking and inviting family home, inside and out, with just the special touches you'd expect from people who know what they're doing.

Low-voltage recessed lighting and plum-speckled slab-granite countertops add to the warmth of the maple kitchen.

Among them:

• The outdoors has joyfully encroached on the bedroom of the Langs' 6-year-old daughter, Lauren. Patty Arnold, their pastor's wife, has painted one wall to resemble a gorgeous garden scene, with a mammoth tree whose branches reach onto the ceiling and adjoining wall, a trellis, a white picket fence and sweet-faced kittens and bunnies nibbling among sunflowers.

• In a downstairs bedroom, reserved for Cary Lang's 15-year-old daughter when she visits from Texas, a flotation bed snuggles into a recessed area reachable only through a bell-shaped contour.

• The fireplace and television in the Langs' family room are set into a 9-foot-tall wall of maple paneling accented with diamonds of metallic-surfaced ceramic tile. Not that unusual, until Jennifer Lang reaches into the paneling and pops open a secret door. Behind the door, a hidden staircase leads to a home office and expansive views of the Sound.

Throughout the house, in fact, the Sound plays a starring role.

Six-year-old Lauren Lang's room features a wall painted to look like the outdoors, complete with white picket fence, towering tree and friendly critters.

From the formal entry, with its 14-foot-high ceiling and recessed lighting, to the French gliding doors leading from the master bedroom to the deck - the entire home is designed so there is a Sound view from every seat, Jennifer Lang says.

The water theme carries through to a dazzling piece of art above the fireplace in the formal living room.

Created by Blue Heron Studios, it's an etched-marble work called "Tsunami Wave," made by polishing the marble's rough side to represent the Langs' love for the sea, boating and water sports.

If there is another theme to the Langs' one-year-old home, it is warmth. Jennifer Lang selected a soft palette for the decor - neutral shades of beige and taupe that dominate the walls, the woods and the furnishings, and also help make a 6,600-square-foot house feel like a home.

"A lot of customers like white walls," she says. "But really light colors give a home a different feel. Warm colors bring the size down and are more inviting. I didn't want anything in cool tones. The Northwest is already dreary and cloudy and gray. It's OK to look at, not to live in."

Jennifer Lang spices up the beige with "a little drama" - shades of dark plum, accents of burgundy and splashes of forest green - and lots of French contemporary touches, in rounded lines and antique door hardware with a little flair.

The Langs' lighting also reflects warmth - low-voltage, recessed cans that radiate just enough ambiance without glaring or distracting, and soft rope lighting within the crown molding of the formal dining room.

One thing you won't find in the Langs' house is a heavy, hanging chandelier. Nothing against the lights themselves, Jennifer Lang says. "I just don't like to clean them."

A paneled fireplace warms the master bedroom, which also has sliding French doors leading to a deck overlooking Puget Sound.

Another constant in the Lang home is texture, in the ubiquitous metallic-touched wall hangings from her two favorite artists, Combs and Butler, and especially in the carpets. Jennifer Lang chose commercial-grade cut pile and loop carpet - complementary shades of beige leading from the entry to the living room and up the stairs, with darker, burgundy-based carpet for the family room and downstairs.

The deviation from the beige scheme was more practical than aesthetic. "Simply for wear and tear," Jennifer Lang says, pointing to the family's two dogs, bulky Fabris and feathery Snowflake.

Practicality also seems behind the Langs' entry into the homebuilding and design business.

Cary Lang grew up a somewhat unwilling apprentice to his father, who was also a builder. "I didn't really have a choice," Cary Lang says. "I started getting involved in grade school."

He and Jennifer incorporated their business about 10 years ago and have completed developments of $230,000 to $550,000 homes in Federal Way and near Lake Tapps, with a new one under way in Newcastle.

A door concealed in the family-room paneling opens to reveal a staircase that leads to a home office.

Lang says his company works with stock designs and then, just as in his own home, adds personal touches. And once Cary Lang has handled the land purchase, real-estate deals and construction supervision, Jennifer Lang steps in to work on design and color.

"She spends a lot of time on colors," Cary Lang says. "And she's always one off of the typical color. Whether it's a design in a tile border or an accent touch, it just looks different. She brings it all together."

For all their experience, the Langs' dream home didn't emerge without a few minor nightmares.

First there was the septic issue. Because the drainage is above the lot, the house had to be "pushed down," Cary Lang says, to ensure a level back yard. (Hence the multi-levels in the house.)

Then there were the official eyebrows raised over the 20-foot-high wall of concrete the Langs poured between the four-car heated garage and the sport court.

The granite-slab countertop for the kitchen island arrived in two huge pieces - straight-edged, when they were supposed to curve - but at least it arrived safely. Plumbing for one bathroom fell off the truck on its way from Canada.

Still, though, after pushing for pre-Christmas completion and taking on some physical tasks himself, Cary and Jennifer Lang moved in December after just nine months of construction.

"It was stressful," Cary Lang says. "I'm not sure I want to do a house this big again."

So for now they're just thinking of extending the water theme - with a pool.

Sandy Dunham is a freelance writer living in Bonney Lake.