高对比度模板矢量海报

将上传的肖像转化为高对比度的矢量海报插画。

风格要求：
- 大胆的模板/宣传海报美学
- 扁平矢量艺术
- 仅使用 3–4 种颜色
- 纯红色背景
- 面部以灰度色调呈现（2–3 个扁平阴影层）
- 黑色粗外轮廓线
- 无渐变
- 无纹理
- 无写实效果
- 锐利干净的边缘
- 海报化阴影
- 居中头部构图
- 极简但强烈的面部特征
- 平面设计风格
- Adobe Illustrator 矢量外观
- 高对比度
- 平滑的几何阴影形状

输出：
清晰、干净、可缩放的矢量风格肖像。

Transform the uploaded portrait into a high-contrast vector poster illustration.

Style requirements:
- Bold stencil / propaganda poster aesthetic
- Flat vector art
- 3–4 color palette only
- Solid red background
- Face rendered in grayscale tones (2–3 flat shadow layers)
- Black thick outer contour lines
- No gradients
- No texture
- No photorealism
- Sharp clean edges
- Posterized shading
- Centered head composition
- Minimal but strong facial features
- Graphic design style
- Adobe Illustrator vector look
- High contrast
- Smooth geometric shadow shapes

Output:
Crisp, clean, scalable vector-style portrait.