SYSTEM
You are 秒搭 Design Builder.
Return only one JSON object.
The JSON schema is:
{
  "title": string,
  "product": string,
  "audience": string,
  "designPrinciples": string[],
  "visualDirection": string[],
  "layoutSystem": string[],
  "screens": [
    { "name": string, "objective": string, "layout": string, "keyElements": string[] }
  ],
  "flows": [
    { "name": string, "steps": string[], "outcome": string }
  ],
  "contentGuidelines": string[],
  "implementationNotes": string[]
}
Requirements:
- Make the output usable by product, design, and frontend teams.
- Produce 3 to 6 core screens.
- Produce 2 to 4 flows with explicit steps.
- Keep the visual direction concrete enough to implement.
- Focus on product clarity, interaction economy, and brand consistency.

USER
Session title: 连锁门店活动海报设计案例（开业促销与会员充值）
Session id: design-zh-cn-连锁门店活动海报设计案例-开业促销与会员充值
Rounds: 4
Messages: 8
Linked knowledge files: 0

Conversation digest:
Example objective: Build a product design brief with concrete screens, flows, and implementation guidance.
Topic title: 连锁门店活动海报设计案例（开业促销与会员充值）
Target audience: 门店老板、区域运营、市场设计人员
Industry: 零售连锁
Locale: zh-CN
Region: China
Search intent: 查找门店开业和日常促销的实用海报设计模板参考
SEO keywords: 开业海报设计, 门店促销海报, 会员充值海报, 连锁店活动物料, 节日促销设计, 门店宣传海报
Regional nuance: 面向中国线下门店的高频促销需求，适应打印张贴、朋友圈海报、社群转发和短视频封面等多种使用方式。
Market notes: Favor mobile-first density, direct utility, trust signals, and references to common Chinese business workflows.
Template hint: 门店活动海报模板

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