PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment appears to be a medium-weight brushed cotton or flannel blend. It possesses a matte finish with low specularity (no shine). The simulation must treat the material as semi-structured; the collar and cuffs should hold rigid shapes, while the torso and sleeves should exhibit soft, heavy draping rather than fluid, silky movement. - **Key Features:** The specific "windowpane" check pattern (green with white/purple grid) requires precise volumetric mapping to avoid warping. The vertical pleats/tucks at the waist hemline create a "blouson" silhouette that must be preserved. The white buttons and the dropped shoulder seams are critical structural anchors. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** Unlike the user's current skin-tight halter top, the target garment is a relaxed/oversized fit. The simulation must generate volume *outward* from the user's torso. The dropped shoulders of the shirt must sit lower on the user's deltoids. The sleeves are full and should obscure the user's current arm contours, gathering slightly at the wrist cuffs due to the balloon-sleeve cut. The hem of the shirt should sit loosely over the waistband of the user's skirt. - **Occlusion Handling:** The user's hair is slicked back, simplifying neck occlusion. However, the user's hands (positioned at thigh level) must be segmented; if the sleeves are long, they should naturally drape near the wrist/knuckles, but the fingers must remain visible and layered *over* the fabric if they interact. The current black halter straps and arm warmers must be fully erased to prevent texture bleed-through at the open collar area. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user is illuminated by a soft, diffused light source coming from the front-left, casting a soft shadow on the wall to her right. The Green Shirt must generate self-shadowing (ambient occlusion) under the collar, beneath the bust, and inside the folds of the sleeves. The lighting on the fabric needs to graduate from brighter on the left to slightly darker on the right to match the scene's global illumination. - **Color Calibration:** The source image of the cloth has neutral, flat lighting. The green albedo needs to be slightly warmed to match the indoor temperature of the user's photo. The white grid lines on the shirt should align with the white point of the background wall to ensure integration. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** The user's entire head (hairline, ears, gold earrings, face shape, and neck up to the clavicle) is a strict "Keep Area." No pixel modification is permitted above the collar line. - **Body Integrity:** The simulation is strictly prohibited from slimming the user's waist or hips. The skirt, belt, and legs must remain untouched, except where physically covered by the new shirt's hem. The user's stance and shoulder width must remain constant; the clothes must adapt to the body, not the reverse.