PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a fitted, navy blue knit top (likely cotton-jersey or spandex blend). It has a matte finish with low reflectivity. It is pliable and stretchy, designed to hug body contours rather than drape loosely. Light absorption is high due to the dark color; highlights will be soft and diffuse, not specular. - **Key Features:** Wide square neckline (approaching a sweetheart cut), short cap sleeves, and a fitted bodice. The seamless shoulder construction and the specific dark navy hue must be preserved. The lack of visible buttons or zippers implies a pull-over structure. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** Due to the target user's "arms raised/hands behind head" pose, the shoulder physics are critical. The cap sleeves must lift and bunch slightly at the apex of the shoulder joint, while the fabric under the armpit will stretch taut upward. The neckline will sit higher on the clavicle than in the standing source image due to the lifted shoulder girdle. The bodice must follow the user's torso skin tightly, replacing the current loose, flared peplum silhouette. - **Occlusion Handling:** - **Hair:** The long dark hair falling over the user's left shoulder (viewer's right) and down the back is a primary occlusion layer. The new blue fabric must be rendered *behind* these hair strands. - **Jewelry:** The necklace sitting on the chest must be masked and layered *over* the new garment if the neckline intersects with it. - **Anatomy:** The user's inner arms and armpits are exposed; the garment must pass underneath the armpits correctly without clipping into the skin. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The target environment utilizes soft, diffuse lighting originating from the front-left (viewer's left). The generated garment must exhibit soft shadowing on the viewer's right side (ribcage and side torso) and under the bust. Shadows should be deep due to the navy fabric, while highlights should be subtle and consistent with the softbox-style lighting of the target room. - **Color Calibration:** The source navy blue is cool-toned. It may need a slight warm adjustment to match the color temperature of the target image's skin tones and room ambiance. Ensure the navy does not crush into pure black in the shadowed areas; texture detail must remain visible. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** Absolute freeze on the user's face, ears, jawline, and the specific texture of the neck skin. The hairline must remain untouched. - **Body Integrity:** Do not alter the user's torso width or arm thickness. The simulation must adhere to the user's actual physical boundaries (under the current loose top), not the silhouette of the puffy clothing being replaced. The underarm skin texture and arm muscle definition must remain original.