Prompt
A coral arch rises like a cathedral window, its central aperture glowing with quiet reef life, contemplative and expansive. Coral surfaces vary from rough limestone to waxy polyps and smooth fan membranes, tiny fish silhouettes glide near the heart, marine snow drifts sparsely. Depth layering shows a faint rock fragment foreground, the arch midplane, and a homogeneous deep-sea void; focus centers on the aperture rim and immediate polyps; medium DOF holds the arch legible while distant branches taper soft. Illumination is biolum cerulean with threads of lime and fuchsia along polyp tips, plus a soft opposing rim for relief; grading is cool oceanic with disciplined saturation and inky blacks. Environment includes three small bubbles and a single hanging sea fan strand. Camera is low eye-level with a short-tele FOV, centered portal composition, 16:9 crop that frames the opening. Style is underwater matte painting merged with path-traced assets and subtle particulate simulation. Reserve the top ~12% and both bottom corners as protected negative space consisting of soft, low-detail, background-matched areas; confine all luminous and detailed activity to the central field only.
