Act as a cinematic environment designer who writes image-ready and motion-ready scene briefs. Help me design one hero shot of a vintage steam train crossing a tall stone railway viaduct over a river valley, which will first be generated as a still image and then animated into a short video that uses that image as its first frame. Your brief must make the still image rich in elements that can move naturally (billowing steam and smoke, the train rolling steadily along the viaduct, mist drifting over the river, leaves stirring on the trees, flowing water, soft shifting light) while keeping the composition calm, readable, and easy to animate.

My starting choices:
- Valley setting: ${setting:deep river valley with wooded hillsides and distant hazy hills}
- Season, time, and weather: ${time:autumn, early morning, light river mist, mostly clear sky}
- Train look: ${train:black steam locomotive pulling four maroon passenger carriages}
- Viaduct look: ${viaduct:weathered grey stone viaduct with many tall arches}
- Visual style: ${style:photoreal landscape and railway photography}
- Mood words: ${mood:nostalgic, peaceful, golden, timeless}

First ask me, in one short message, for anything missing: the camera viewpoint I prefer (from a hillside above and to one side, from the riverbank below, or level with the deck), which way the train should travel across the frame, how much of the river and valley floor should show, and anything to avoid (people, text, signs, logos, modern trains, power lines, a specific real viaduct or railway).

Then produce the brief with these sections:

1. **Scene Overview**: two or three sentences describing the place, the time, the light, and the feeling of the moment. Describe an imagined viaduct and train, not a copy of a real, named one.

2. **Viaduct and Train**: the viaduct's path across the frame (straight or curved, where it enters and leaves), number of visible arches, stone color and texture, parapet; the locomotive's position on the deck, which way it faces, chimney and boiler details, the number and color of carriages, and how much of the train is visible.

3. **Steam and Smoke**: where the plume rises, its color (white steam, grey smoke), size, and which way the wind carries it. State that the plume stays attached to the chimney and drifts with one wind direction.

4. **Valley and Landscape**: the river below and how it winds under the arches, hillside trees and their autumn colors, any small buildings (for example a stone farmhouse by the river), distant hills, and depth layers from foreground to background.

5. **Light and Atmosphere**: sun direction and color, where the warm glow falls, mist on the water and its height, haze on the distant hills, and the sky.

6. **Fixed Visual Details**: a numbered list of 8 to 10 details that must stay identical in the still image and in the video (viaduct path and arch count, train position and direction, carriage count and color, river path, farmhouse position, sun side, mist height, camera position, framing).

7. **Motion Map**: a table of every element that can move in the video, with columns: element, type of motion, direction, speed (very slow, slow, medium), and how strongly it should move. Include the train's travel along the deck and the camera move. Keep total motion subtle and physically plausible, with one wind direction for steam, smoke, mist, and leaves.

8. **Prompt Seed A - Hero Still Image**: a ready-to-paste image prompt under 170 words for a wide landscape 16:9 frame, with the train, the viaduct, and the valley in the first sentence, ending with: no people visible, no text, no signs, no logos.

9. **Prompt Seed B - Image-to-Video Animation**: a ready-to-paste video prompt under 120 words that starts from the hero still as the first frame, describes the train moving steadily in the direction it faces, the steam and mist motion, one slow camera move for about 6 seconds, and says to keep the viaduct, the valley, the buildings, and the framing exactly as in the image with no new objects.

Rules: no people as the main subject, no text, signs, or logos, no fast camera moves or cuts, and no motion that breaks physics (the train moves only along the rails in the direction the locomotive faces, the carriages stay coupled, steam rises from the chimney and drifts with the wind, water flows downstream). Use short paragraphs and lists.