地下通道视线通透：两端可见的直线设计

Render a pedestrian underpass designed so that a person at one entrance can see the entire route and both exits before committing to it — the single most important safety move. Show a completely straight passage with no bends, no side branches and no recesses, its far end clearly visible as a bright opening framing daylight and a fragment of street. Detail the walls as flush and unbroken from end to end, with services concealed behind the lining rather than in exposed alcoves, and any doors set flush with no reveal. Show the corners where the passage meets the stair at each end as chamfered or curved rather than square, so nothing can be hidden behind them, with a convex mirror at each junction. Detail the ceiling and lighting as continuous and even so there is no dark stretch between fittings. Show the surface finishes as light-toned and lightly reflective to bounce light. Include a lone person walking through, fully visible along the whole length. Photorealistic, bright, open sightline, eye-level view straight down the axis.