Create an ultra-premium dessert advertising poster for a fictional Japanese patisserie "YUKI". FORMAT: 4:5 vertical, minimalist elegant layout. SUBJECT: a delicate matcha-and-white-chocolate mousse cake with a mirror glaze, a single gold leaf and a dusting of matcha, a clean knife-cut cross-section showing airy layers. BACKGROUND: soft sage-to-cream gradient with subtle rice-paper texture. LIGHTING: soft diffused light, glossy glaze highlights. TYPOGRAPHY: refined minimal logo "YUKI" top-center, tiny tagline "Quiet sweetness" bottom. FINISH: 8k, hyper-realistic food photography, serene finish.