Chen Hao folded the blueprint and stuffed it into his work uniform pocket. His fingers touched the strip of cloth in his palm, and he pressed it gently. The wound didn't hurt much anymore, just a little itchy.

He stood up, the chair leg scraping against the floor. Nana had already opened the toolbox, taking out the last set of ore modules, her metal fingers flipping through them quickly.

“We’re still missing three ground lights,” she said. “They’ll be installed at the corner of the maintenance passage, under the stairs, and to the right of the vent.”

“I remember.” Chen Hao grabbed a small wrench. “The spot where I almost tripped last time must be secured this time.”

They went to repair the passageway first. The crack in the wall had been cut a bit too deep before, and the resin hadn't completely dried yet; it was loose at the slightest touch. Chen Hao squatted down, used a bracket to support the mineral slab from behind, and screwed in two miniature fixing nails.

“This thing is harder than a jigsaw puzzle.” He wiped the sweat from his forehead. “If you put it together wrong, you can take it apart. This is a one-off deal for us.”

"The allowable error is 0.5 millimeters." Nana adjusted the focal length of the optical lens. "The current deviation is 0.3, which is safe."

“You’re quite accurate.” He grinned, then his knee clicked as he stood up. “Getting old.”

“Your biological age is 26 years and 4 months.” She handed over a cooling gel patch. “I recommend reducing prolonged knee flexion.”

"Stop reading the data, it sounds like a doctor prescribing medicine." He took the patch, applied it to his knee, and let it cool. "Let's go, next one."

The lights under the stairs were the hardest to install. The space was narrow, and it was difficult for a person to squeeze in. Chen Hao struggled twice before finally managing to get into position, and he bumped his head when he reached in to connect the wiring.

"Ouch!"

"A mild risk of concussion has been detected." Nana reached out and pulled him away. "Let me take over."

She reduced the diameter of the robotic arm, deftly screwed the interface tight, and then sealed the edges with translucent resin. Green light shone through the gap, illuminating the side of the steps and forming a soft band of light.

“Alright,” she said. “The tilt has been calibrated.”

"Better than me." Chen Hao rubbed the back of his head. "Let me be your assistant next time."

The last one was next to the ventilation shaft. There were too many pipes, so they could only drill from the side. Chen Hao held the drill bit steady, while Nana controlled the depth. Halfway through drilling, the ore suddenly flashed.

"Temperature fluctuations?" he asked.

“External heat source interference.” She glanced at the readings. “The residual temperature in the pipes is too high, which may affect the startup delay.”

“Then add a heat-insulating pad.” He rummaged through the scraps and found a piece of metal foil, cut it into a circle and put it on. “It’s a makeshift solution, but it’ll work.”

By the time the last lamp was installed, it was already dark.

They returned to the main hall and stood in front of the central control panel. All seventeen points on the screen were lit up with green lights.

"All lights are installed," Nana said. "Shall we turn them on?"

Chen Hao stared at the screen for a few seconds, then suddenly chuckled.

"You mean we've spent the whole day working just to press a button?"

"The essence is system integration and execution verification," she said. "Buttons are just terminal operations."

“You put it more sophisticatedly.” He raised his hand. “Come on, light it up.”

He pressed the confirm button.

The panel took two seconds to respond. During this time, no one spoke.

The first ray of light fell from the restaurant ceiling, a warm green, not glaring. Then, one by one, the floor lamps in the corridor lit up, like a string of slowly flowing stars. The wall lamps followed, and the fox-shaped lamp above the workbench blinked and lit up as well.

But the one at the bottom of the stairs was a beat too late.

“The slow start mode has been triggered.” Nana immediately pulled up the log. “I didn’t turn it off during the debugging process.”

"Switch over manually."

She entered the command, and instantly, the light in the entire corridor became continuous, without any gaps or shadows. The lights in the maintenance corridor also shone steadily, illuminating the previously dark corners.

"It's done." Chen Hao breathed a sigh of relief. "At least it wasn't all for nothing."

He ran around with a photometer, measuring the actual brightness of each area. 220 lux in the restaurant, 140 in the corridor, and 75 in the rest area—all within the standard range.

Only the side of the staircase is a little dark.

"The angle is off by five degrees." Nana made a remote adjustment. "Try again."

She had just finished adjusting the parameters when the backup ore automatically activated, increasing the brightness in certain areas. The side of the steps was clearly visible, even the wear marks on the edges were clearly illuminated.

“Perfect.” Chen Hao put down the instrument. “This time, no one will slip.”

He walked back to the center of the main hall and slowly walked around it.

The entire base was lit. The light wasn't a cold, hard white, but a soft glow with a hint of green, like moonlight falling on leaves. The crooked little animal lamps on the walls no longer looked ugly; in fact, they were kind of cute.

He stood leaning against the newly installed fox-shaped wall lamp, his hand resting on the edge of the lampshade.

“Before, when I got up at night, I would have to stop after taking a few steps in the dark,” he said, “for fear of stepping on something I shouldn’t have.”

“We don’t need to now.” Nana stood beside him, the optical glasses reflecting the light that filled the room. “The entire walking path is visible.”

“It’s not just the visible things,” he said softly. “It feels different. Like… home.”

Nana didn't say anything, but the database automatically marked a record: "Peak of positive human emotional feedback".

She retrieved a pre-saved audio clip and played it softly.

The sound of a guitar begins, a very simple melody, playing on a loop.

"When did you record this?" he asked.

“Three days ago,” she said, “I anticipated the emotional fluctuations that might occur when the lighting was completed, and I prepared in advance.”

"You're quite observant," he chuckled. "But isn't this music... a bit too quiet?"

"Matching the current atmosphere."

“That’s true.” He looked around. “It’s a real shame that no one is looking at such a bright place.”

“The records are archived,” she said. “In the future, people will know what we did.”

He nodded and didn't say anything more.

After a few minutes, he suddenly spoke: "Nana."

"exist."

"We have lights now."

"confirm."

"There are tables, chairs, and cabins where you can sleep."

"Fully functional".

What's missing?

She waited a few seconds. "Unrecognized request."

“A bathroom,” he said. “It’s time to build a bathroom.”

Nana's optical glasses flashed.

"The suggestions for improving quality of life have been received," she said. "Functional zoning needs to be planned."

“First, let’s think about the location.” He slowly slid down against the wall, leaning against the fox lamp. “It can’t be too far from the rest area, and it can’t be next to the kitchen. Drainage is a problem…”

His voice lowered, and his eyelids began to droop.

Nana looked down at him and noticed that his breathing had become steady.

But she didn't wake him.

The lights were still on, evenly distributed in every corner. In the center of the main hall, Chen Hao sat leaning against a wall lamp, nodding his head slightly, still clutching a photometer in his hand.

Nana lowered the brightness in some areas, leaving only basic lighting.

She stood still, her optical lens continuously scanning environmental parameters, and classified this project as an "S-level living facility relocation case".

The wind swept across the roof outside the door, making a slight scraping sound.

Chen Hao raised his hand, touched the strip of cloth in his palm, and slowly loosened his fingers, allowing the photometer to slide down to his side.