At the new Jimmy D’s diner-style restaurant and its adjacent bar, The Map Room, they’re giving the classics a thoroughly modern twist.

First, there’s the location: the midcentury-style Garrett’s Desert Inn on Old Santa Fe Trail, which opened in 1958 and had its heyday in the ’60s and ’70s. Jimmy D’s occupies the space previously housing Santa Fe Bite. The Map Room was once a travel agency owned by the Garrett family; most recently, co-owner Jennifer Day said, it was nothing but an empty room.

Then there’s the décor (much more on that in a moment): Jennifer Day — who happens to be an accomplished member of the American Society of Interior Designers and artist in addition to entrepreneur and multi-restaurant owner — has transformed the spaces into lavish homages to retro midcentury modern style.

And then there’s the food itself: The kitchen puts some creative spins and elevated presentations on casual diner and American comfort food classics, offering Southern-influenced dishes alongside a few New Mexico favorites, from-scratch cakes and pies along with burgers, fries and milkshakes.

“We tried to build a place that people want to come to a couple of times a week,” said co-owner Jimmy Day (who also happens to be Jimmy D’s namesake).

And people have been coming. They’ve had a steady crowd since a quiet opening May 10, Jennifer Day said, with a mix of locals, tourists and downtown employees dining in or grabbing takeout orders. New Mexico Fine Dining’s newest restaurant can seat about 200, including the large patio filled with vibrant-hued tables and chairs, where they’ll soon start having live music.

Those colorful tables are just a hint of the pop-art bonanza Jennifer Day created inside Jimmy D’s. Midcentury modern design meets ’60s and ’70s music nostalgia in a bold, bright whirlwind.

Walls are covered with classic album covers and comic books. Jennifer Day created eye-popping, large-scale digital artworks that pay tribute to iconic pop artist Roy Lichtenstein, Keith Haring the Beatles, hippie culture, Andy Warhol and the Velvet Underground, among others. There’s even an honest-to-heaven Velvet Elvis.

The blond-wood tables are paired with an army of sleek plastic midcentury modern-style dining chairs in various colors. Many of the striking pendant lights are George Nelson’s modernist designs.

“It’s a really fun place,” Jennifer Day said. “Santa Fe doesn’t have anything like this.”

If Jimmy D’s is the place for full-out nostalgia, The Map Room is its quieter, Mad Men-esque cousin. Jennifer Day extended an original, exposed wall of rock (the hotel itself is undergoing major renovations) to create a warm and inviting fireplace and banco, covered in an array of plush pillows. Midcentury chairs swivel and tables nest or separate to create a multitude of configurations for sitting, drinking and dining (you can order off the Jimmy D’s menu).

“This is an extremely interactive space,” Jennifer Day said.

On the wall are examples of her own art along with a range of vintage maps, many dating from the 1800s. Most striking: a map of New Mexico’s ghost towns, with pictures and descriptions of each connected by string and pushpins to their corresponding spots on an oversized map of the state.

The large central bar, lined with elegant low-backed stools, serves a full complement of wine, liquor and beer, including New Mexico favorites on tap. House specialty cocktails have cheeky, era-appropriate names like Solid Gold, Totally Atomic, The Taxi Driver and Surely MacLaine.

Over at Jimmy D’s, the menu echos some of the same playful spirit. The French toast casserole ($13) has sausage and banana baked inside, and there’s a fried PB&J on the extensive kids menu (all dishes there, including breakfast and lunch or dinner, are $5 or $6). Starters include pimento cheese, chile poppers and a taco pizza that changes daily (there’s also a daily vegetarian special on the menu, chef Jen Doughty said).

There’s a range of salads and sandwiches, including a grilled cheese with bacon and poblano chile, and meatloaf sliders on Parker House rolls with haystack onions and barbecue sauce (both $12).

The Jimmy’s Burger ($14) is done up in classic In-N-Out style, with two thin 4-ounce patties topped with soft, butter-braised sweet onion, lettuce, tomato and a special sauce that Doughty keeps a closely guarded secret.

Entrees and dinner features range from fish and chips, “fancy” mac and cheese, and chicken enchilada casserole to comfort favorites like country fried steak, meatloaf, and roasted and fried chicken served with potatoes au gratin and collard greens (most entrees are $13-$17). A pastry chef whips up chocolate layer cake, banana pudding, tequila key lime pie and other sweets, and a trio of milkshakes round out a drinks menu of sodas, iced tea and lemonade.

The new spaces bring diversity to the New Mexico Fine Dining portfolio: Bouche and Trattoria A Mano are fine-dining restaurants, The Map Room’s a bar and Jimmy D’s is a family-dining establishment. The Days plan to open the casual-dining Asian restaurant Lucky Goat by July in the former home of State Capital Kitchen, and they’re also aiming for a September reopening of the original Bobcat Bite restaurant on Old Las Vegas Highway.

“If you want something done,” Jennifer Day said with a laugh, “ask a busy person.”

Jimmy and Jennifer Day have been married for 41 years, with two grown children and a 16-year-old who attends Santa Fe High School. They bought their first home in Santa Fe 18 years ago, but they’ve been coming to the city for decades, even as broke newlyweds living in Austin, Texas, who lovingly haunted the local art galleries.

“We’re bringing something truly different” to the city they love, Jennifer Day said. “We want people to have an experience when they come here.”