PHASE 1: VISUAL DECONSTRUCTION - **Fabric Physics:** The source garment is a heavyweight cotton jersey with a matte finish. It exhibits medium stiffness—soft enough to fold comfortably but thick enough to hold an oversized, boxy structure without clinging to the skin. Light reflection should be diffuse with minimal specularity. - **Key Features:** The specific lilac/lavender hue. The "FUTURE" graphic print on the left chest. The ribbed crew neckline. The drop-shoulder construction (seam falls below the natural shoulder point). The longer, elbow-length sleeve hem indicative of an oversized fit. PHASE 2: FIT & DRAPE SIMULATION - **Body Mapping:** Unlike the target's current fitted burgundy shirt, the new lilac tee must sit loosely. On the user's raised right arm, gravity must pull the excess fabric of the oversized sleeve down toward the shoulder, creating deep compression folds in the right armpit/axilla region. On the user's relaxed left side, the sleeve should flare slightly and hang freely, not hugging the bicep. The hemline needs to rise on the user's right side due to the arm lift. - **Occlusion Handling:** The user's jawline and neck are the primary boundaries. There are no hair or jewelry occlusions to manage. However, the simulation must strictly respect the boundary of the user's beige shorts; the new t-shirt is longer and will overlap the waistband, requiring a realistic shadow cast onto the shorts. PHASE 3: ENVIRONMENT & LIGHTING - **Light Match:** The user image features a strong, hard light source coming from the left (user's right), creating sharp, high-contrast shadows on the right side of the torso (user's left). The new garment must render with bright highlights on the left deltoid and chest, transitioning to deep, sharp shadows on the right side and under the raised arm. - **Color Calibration:** The user's environment has a warm, yellow-toned background. The cool lilac of the source shirt must be subtly color-graded to accept warm ambient bounce light from the background to avoid looking like a "cut-and-paste" sticker. PHASE 4: IDENTITY PROTECTION - **Facial Lock:** The user's entire head, including the beige cap, facial features, and ears, must be pixel-locked. The skin tone on the neck and arms must remain unaltered. - **Body Integrity:** DO NOT alter the user's lean muscular build. While the shirt is oversized, the underlying body mesh (shoulder width, waist size) must remain accurate. The exposed arms must retain their current muscle definition and lighting.