PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a medium-weight flannel or brushed cotton blend. It has a matte finish with high light absorption and zero specular highlights. The simulation must render "micro-fuzz" texture softness rather than a crisp, synthetic sheen. It possesses moderate stiffness—it will hold the collar shape but drape vertically without clinging to the skin. - **Key Features:** The tartan/plaid pattern alignment must remain consistent across seams. The structured collar, the specific arrangement of the white contrast buttons, and the slightly curved bottom hemline must be preserved. The drop-shoulder seam construction of the source garment must be maintained to retain the "oversized" aesthetic. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** Unlike the current tight-fitting ribbed corset top, the flannel shirt must sit loosely. The simulation must create a volumetric "air gap" between the user's waist and the fabric to reflect the boxy cut of the shirt. The fabric should hang vertically from the shoulder line, ignoring the user's inward waist curve. Slight bunching/stacking of fabric is required at the elbows due to the user's relaxed, slightly bent arm position. The shirt should be rendered untucked, overlapping the waistband of the green cargo pants. - **Occlusion Handling:** The user's long dark hair (ponytail and loose strands near the neck) must be segmented and layered *over* the new shirt collar. The black handbag and the user's left hand are positioned away from the torso, minimizing interaction, but the left cuff must not clip through the hand or bag handle. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user is in an indoor environment with diffuse artificial lighting coming primarily from the front-right. Shadows on the new garment must cast towards the user's left side (viewer's right). The lighting is soft; deep black shadows should be avoided in folds, utilizing softer ambient occlusion instead. - **Color Calibration:** The target room has pink walls, creating a warm ambient light bounce. The neutral brown/beige of the source shirt must be color-graded slightly warmer to accept this pink spill, preventing the shirt from looking like a sterile "cut-and-paste" from the white studio background. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** The user's entire head, including the hairline, loose hair strands, neck shape, and facial expression, must be strictly masked and frozen. The skin tone of the upper chest (if visible through an open collar) must perfectly match the user's facial complexion. - **Body Integrity:** The user's natural shoulder width and hip dimensions must be preserved. The simulation is forbidden from slimming the user to fit the clothes; the clothes must expand to fit the user. The green cargo pants and the background environment (mirror, curtains) must remain pixel-perfectly unchanged.