diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 9957b4f..de8b4d1 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -26,6 +26,10 @@ jobs:
       - name: Build
         run: bun run build
         working-directory: site
+        env:
+          # Optional arena backend (see worker/README.md); empty = local-only votes.
+          VITE_ARENA_API: ${{ vars.VITE_ARENA_API }}
+          VITE_TURNSTILE_SITE_KEY: ${{ vars.VITE_TURNSTILE_SITE_KEY }}
       - uses: actions/configure-pages@v5
       - uses: actions/upload-pages-artifact@v3
         with:
diff --git a/README.en.md b/README.en.md
index 0a261d1..6023459 100644
--- a/README.en.md
+++ b/README.en.md
@@ -37,6 +37,12 @@ Pending: Mistral Medium 3.5 · GLM-5.1 · Qwen3.7-Max (PRs welcome)
 
 > This table is a hand-maintained snapshot; the site's registry section is generated live from `models/*.json` and is authoritative.
 
+## Arena blind battles & community board
+
+- Each case defaults to **Arena mode**: two anonymous artifacts battle (A / B / Neither) and identities reveal only after you vote; switch to **Demo Show** to browse everything (tabs are grouped by model — a model with several harnesses can be viewed singly or side by side).
+- Casting 03 votes in each case unlocks the **community leaderboard**, ranked by Bradley-Terry scores (the LMSYS Chatbot Arena approach); "neither" counts separately as both-bad.
+- Votes stay in the browser by default; deploying `worker/` (Cloudflare Worker + D1 + Turnstile, free tier) upgrades the board to sitewide crowdsourced data — see [worker/README.md](./worker/README.md).
+
 ## Structure
 
 ```
diff --git a/README.md b/README.md
index f55dce3..bafc558 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,12 @@ NAGI STUDIO 的 LLM 测评案例集：同一段提示词，不同「模型 × Ha
 
 > 此表为人工维护的快照；站点上的「模型阵容」表由 `models/*.json` 实时生成，以站点为准。
 
+## Arena 盲评与社区榜单
+
+- 每个案例默认进入 **Arena 模式**：随机抽两份产出匿名对战（A / B / 都不好），投完票才揭晓身份；右上角可切到 **全部查看**（按模型分组浏览，同一模型多个 Harness 可单看或并排对比）。
+- 在两个案例各投满 03 票后解锁**社区榜单**：按 Bradley-Terry 评分排名（LMSYS Chatbot Arena 同思路），「都不好」单独计入双败。
+- 投票默认存浏览器本地；部署 `worker/`（Cloudflare Worker + D1 + Turnstile 防刷，免费档即可）后自动升级为全站众包数据，步骤见 [worker/README.md](./worker/README.md)。
+
 ## 结构 / Structure
 
 ```