A big reason for the boom in fast-casual chains has been the renewed embrace of that old axiom "you are what you eat." Their salad and stir-fry options are fresher than meals you get at your typical burger joint, with more vegetables and fewer mystery ingredients. It's still fast food, of course, just better for you.

Honeygrow, a Philadelphia-bred fast-casual chain that has been planting its all-natural flag up and down the Eastern Seaboard, has taken that healthy lifestyle philosophy in an architectural direction with its new Fishtown headquarters on Front Street. You could call it, "You are what you inhabit."

Ever since Honeygrow founder Justin Rosenberg opened his first location at 16th and Sansom in 2012, he saw the venture as a disrupter: He wasn't merely promoting a new style of eating; he was also pioneering a fresh kind of business culture. Honeygrow was one of the first chains to allow diners to customize their orders on touch pads. It was also big on storytelling, and it used art, videos, and music to shape a hip identity that went beyond food.

There was just one problem. Even as Rosenberg preached a new-gen business style, Honeygrow's headquarters were housed in a buttoned-up, limestone-clad Center City office building crammed with suited lawyers and bankers. Because of the building's odd layout, finance and creative types were siloed in separate corridors, making it difficult to nurture the team culture Rosenberg was seeking.

Using office design to express a brand and foster team spirit happens to be one of the biggest workplace trends right now. Determined to find a better fit for Honeygrow, Rosenberg cast his gaze north, to the former manufacturing precincts of Fishtown and Kensington, where a growing number of the city's craft food producers - breweries, distillers, bakers, and coffee roasters - have settled.

The original idea was to rent a modest space in an old factory, redolent with the memories of an earlier generation of makers. Then Rosenberg and Honeygrow president David J. Robkin bumped into developer Greg Hill, who had just acquired a nondescript warehouse at Front and Oxford Streets. Sprawling over more than 18,000 square feet, the one-story building was a little bland, but big enough to house an industrial-size kitchen and training center, as well as offices.

Now, a visit to Honeygrow's new headquarters produces a clash of sensations. Situated in a quintessential North Philadelphia landscape, the building is jammed hard against the superstructure of the Market-Frankford El and bracketed by empty lots. Honeygrow is clearly not in Center City anymore.

But once inside, you could be in laid-back and luxe northern California. Dappled light flutters into a serene rustic-industrial main space, and a towering blue spruce tree fills the huge windows on the east wall. Instead of the usual cubicle dividers, the desks are separated by planters thick with glossy greens. The background noise comes from the gentle murmur of fountains, and a small "oasis" garden offers employees a Zen refuge. The rumbling El seems very far away, indeed.

Like a salad, the design is an intentional blend of familiar ingredients. The signifiers of the industrial past - casement windows, skylights, graffiti art - have all been imported into the space and remixed by Richard Stokes, the architect responsible for staging the look of many homegrown Philadelphia eateries. He designed La Colombe on Frankford Avenue, Talula's Garden on Washington Square, Parc on Rittenhouse Square, and, most recently, Wm. Mulherin's Sons, an Italian restaurant that inserted itself into the shell of a 19th-century whiskey distiller on Front Street - Honeygrow's closest neighbor.

At Honeygrow, Stokes fused his restaurant aesthetic with office design to produce a work space that encourages socializing. Yes, there are work tables and a few private offices, but there are also living room lounges with sofas. At Rosenberg's request, Stokes inserted a library on the mezzanine. It's a screen-free zone, meant for contemplation and quiet conversation.

A day at Honeygrow can feel like a millennial dream world. With the extra space, Stokes created a test kitchen and cafeteria that doubles as a training room. But almost daily, the tables are pushed aside so employees can practice yoga together. Rosenberg, a big music fan, also keeps a Gretsch electric guitar by his desk for de-stressing riffs. A new video (Honeygrow hosts an entire collection on Vimeo) celebrating the headquarters' completion features Fishtown band Cold Fronts singing "Primetime," with the lyric, "We can make it better."

Along with the industrial elements, Rosenberg brought in several well-known mural artists to formalize Honeygrow's street cred. Several murals were installed along Front Street to activate the building's solid facade. Kid Hazo's contribution - thick black letters on a white background declaring "Another Amazing Mural" - brilliantly subverts the whole form.

The irony is that Rosenberg had to explain that he didn't want the artists to depict the Honeygrow brand literally. Philadelphia muralist NDA had originally proposed "something with vegetables," Rosenberg said. "I told him it didn't have to represent our business."

The goal was to inspire creative thinking, not a one-note corporate environment, he said. "Who wants cheesy pictures of farms?" NDA instead came up with a piece more in his usual style, showing disconnected body parts.

The biggest innovation at Honeygrow's headquarters is the most ordinary. In addition to the test kitchen, Honeygrow was able to install an industrial-size commissary that can serve the entire chain. There are professional roasting ovens and refrigerators. Before it opened, each Honeygrow location had to have its own complement of kitchen equipment for food prep - a highly inefficient approach.

The central kitchen should help Honeygrow improve its quality control. Now with 15 locations, Honeygrow has plans for many more. Having crafted an identity, it can devote itself to crafting healthful food.