PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a medium-weight cotton jersey. It possesses a matte finish with low reflectivity. The simulation must treat the material as breathable but substantial, resulting in soft, tubular folds rather than sharp creases. It has high drape gravity, meaning it will hang vertically and away from the body rather than clinging to skin contours. - **Key Features:** The oversized/boxy silhouette is critical; the drop-shoulder seams must be preserved and not realigned to the user's natural shoulder line. The high crew neckline with the ribbed collar band, the wide elbow-length sleeves, and the straight bottom hemline must be maintained. The vibrant lime green hue requires preservation without oversaturation. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** Unlike the current tight navy top, the new garment introduces significant volume. The simulation must expand the silhouette around the waist and torso. On the user's right side, the sleeve should hang straight and open due to the straight arm. On the user's left side, the sleeve will interact with the bent elbow; the fabric should bunch slightly at the inner elbow and drape closer to the forearm. The hemline should fall over the waistband of the jeans, likely covering the top button area. - **Occlusion Handling:** 1. **Hair:** The user's dark wavy bob touches her shoulders and neck. The new high collar will sit higher than the current one-shoulder top; the hair must be segmented and masked to layer *over* the new green collar and shoulders. 2. **Left Hand/Pocket:** The user's left hand is tucked into the jeans pocket. The new shirt is long and loose; the simulation must determine if the hem drapes *over* the wrist or gets tucked behind it. Ideally, the hem should drape naturally over the wrist area, potentially partially obscuring the hand-in-pocket entry point. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user image features soft studio lighting coming from the front-right, casting subtle shadows to the user's left (ground shadows and neck shadows). The new garment must generate self-shadowing on the user's left side of the torso and under the left sleeve to match this directionality. - **Color Calibration:** The lime green is highly reflective. The render needs to calculate global illumination where the green fabric casts a subtle green color bleed (bounce light) onto the underside of the user's jaw and neck area to integrate it realistically into the scene. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** The user's face, skin tone, earrings, and specifically the hair volume and shape must be frozen and masked out of the generation process. - **Body Integrity:** Strictly forbid any "slimming" or "fitting" algorithms that would attempt to shrink the oversized shirt to match the user's current slim silhouette. The user's hips, legs, and the texture/geometry of the jeans below the new shirt's hemline must remain pixel-perfectly unchanged.