Character poster, brand, night scene, elegant.

Using the provided reference image as the character and design basis, transform a clean Live2D model reference sheet into a polished VTuber debut announcement poster, while retaining the original character design, hoodie, headphones, collar, star and constellation elements, and the overall purple-blue night color tone. Change the composition from a full-body reference sheet to a more dramatic half-body key visual, showing the character sitting at a streaming desk, one hand propping up their cheek, in a cozy nighttime bedroom streaming room. Add a starry city night window background, curtains, hanging star decorations, a glowing monitor, a desktop microphone, a keyboard/controller, and a drink cup, supplemented by soft cinematic lighting and sparkling atmospheric effects. Retain Yume Asta branding, and make the layout feel like an X/Twitter thumbnail or promotional key visual. Add dense decorative typography and framed info panels, in an elegant Japanese idol/VTuber promotional style: a large headline containing the Japanese name and the romanization "Yume Asta", a short poetic tagline, 4 boxed profile sections labeled "Profile", "Like", "Keyword", and "配信スタイル", and a smaller tag/community box in the lower left corner. At the bottom center, add prominent glowing large headlines "VTuber Debut" and "Coming Soon", and below them add a ribbon-style banner with Japanese debut stream text. The overall effect should be richly detailed, dreamy, bright, and premium, like an official VTuber debut teaser poster.