diff --git a/app/server/db.mjs b/app/server/db.mjs
index 4e781e3..262d841 100644
--- a/app/server/db.mjs
+++ b/app/server/db.mjs
@@ -5,6 +5,7 @@ import fs from 'node:fs';
 import path from 'node:path';
 import crypto from 'node:crypto';
 import { fileURLToPath } from 'node:url';
+import { loadCert, CERT_BY_TITLE } from './demo-certs.mjs';
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 export const DATA_DIR = process.env.DATA_DIR || path.join(__dirname, '..', '.data');
@@ -412,6 +413,27 @@ export const DEMO_ROWS = [
   ['证书技能', '计算机技术与软件专业技术资格（软件设计师）', '参加', '国家级', null, '工业和信息化部', '2025-11-08', null, 'ongoing',
    '备考软件设计师（中级）', '', ['软考'], ['职业发展'],
    {}, {}],
+  ['竞赛', 'ACM-ICPC 国际大学生程序设计竞赛', '核心', '国家级', '银奖', '中国大学生程序设计竞赛组委会', '2025-10-18', '2025-10-19', 'finished',
+   '赛区内团队排名前 5%，与队友分工负责图论与动态规划、数据结构与搜索方向', '亚洲区域赛银奖', ['算法', '团队协作'], ['学业深造'],
+   { my_work: '图论建模与状态转移设计', team_members: '王五、赵六' }, {}],
+  ['竞赛', '中国大学生计算机设计大赛', '主导', '国家级', '二等奖', '中国大学生计算机设计大赛组织委员会', '2025-05-10', '2025-07-30', 'finished',
+   '作品《基于流量特征的入侵检测系统》，负责整体方案设计与检测算法实现', '全国总决赛二等奖', ['计算机', '安全'], ['学业深造'],
+   { my_work: '方案设计、检测算法实现', team_members: '张三、李四' }, {}],
+  ['竞赛', '第三届"强网杯"全国大学生网络安全挑战赛', '核心', '国家级', '二等奖', '战略支援部队信息工程大学', '2024-11-09', '2024-11-11', 'finished',
+   'CTF 攻防模式，负责 Web 渗透与 RSA 共模攻击类密码题', '半决赛二等奖', ['CTF', '密码', '安全'], ['职业发展'],
+   { my_work: 'Web 渗透与密码工具编写', team_members: '张三、王五' }, {}],
+  ['竞赛', '"挑战杯"全国大学生课外学术科技作品竞赛（省赛）', '核心', '省市级', '三等奖', '共青团重庆市委员会', '2025-03-15', '2025-06-20', 'finished',
+   '作品「基于流量特征的入侵检测研究」，负责研究报告撰写与答辩', '省赛三等奖', ['科研', '学术'], ['学业深造'],
+   { my_work: '研究报告撰写' }, {}],
+  ['竞赛', '全国大学生英语竞赛', '参加', '省市级', '三等奖', '高等学校大学外语教学研究会', '2024-04-14', '2024-04-14', 'finished',
+   'C 类笔试，词汇与阅读优势明显', 'C类省级三等奖', ['英语'], ['学业深造'],
+   { score: '88' }, {}],
+  ['竞赛', '院"新生杯"程序设计竞赛', '参加', '二级学院', '一等奖', '计算机网络学院', '2023-11-18', '2023-11-18', 'finished',
+   '大一入门竞赛，C 语言实现图书管理系统', '院级一等奖', ['编程'], ['学业深造'],
+   {}, {}],
+  ['竞赛', '全国大学生密码技术竞赛', '参加', '国家级', null, '中国密码学会', '2025-11-20', null, 'ongoing',
+   '组队备战国赛（SM9 聚群签名方向）', '', ['密码', '学术'], ['学业深造'],
+   {}, {}],
   ['实习实践', '某安全公司渗透测试实习生', '参加', null, null, '某网络安全科技有限公司', '2025-07-01', '2025-08-25', 'finished',
    '参与企业授权渗透测试项目 3 个，编写测试报告', '获实习优秀评价', ['实习', '安全'], ['职业发展'],
    { position: '渗透测试实习生', mentor: '陈工' }, {}]
@@ -446,27 +468,27 @@ export const DEMO_PROFILE = {
   resume: DEMO_RESUME
 };
 
-// 演示附件用真实 PNG（1x1，可在预览查看并进入综测证明材料）
-const DEMO_PNG = 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==';
-
 
 // 学期: { term, gpa, rank, total, courses: [课程名, 学分, 分数, 绩点, 类别][] }
+// 学期: { term, gpa, rank, total, courses: [课程名, 学分, 分数, 绩点, 类别][] }
+// 演示成绩与成绩梯度公式一致：分段线性 gp（90→4.0 至 100→5.0，80→3.0 至 89→3.9 …），
+// 学期 GPA 为分类加权（必修 1.2 / 专业选修 1.1），与 grades_overview 的综合算法结果吻合。
 export const DEMO_SEMESTERS = [
-  { term: '2023-2024-1', gpa: 3.42, rank: 38, total: 156, courses: [
-    ['高等数学（上）', 5, 78, 3.0, '必修课'], ['大学英语（一）', 3, 85, 3.7, '必修课'], ['程序设计基础', 4, 91, 4.0, '必修课'],
-    ['思想道德与法治', 2, 88, 3.9, '必修课'], ['体育（一）', 1, 82, 3.5, '必修课']
+  { term: '2023-2024-1', gpa: 4.13, rank: 48, total: 156, courses: [
+    ['高等数学（上）', 5, 78, 2.8, '必修课'], ['大学英语（一）', 3, 85, 3.5, '必修课'], ['程序设计基础', 4, 91, 4.1, '必修课'],
+    ['思想道德与法治', 2, 88, 3.8, '必修课'], ['体育（一）', 1, 82, 3.2, '必修课']
   ]},
-  { term: '2023-2024-2', gpa: 3.61, rank: 29, total: 156, courses: [
-    ['高等数学（下）', 5, 84, 3.7, '必修课'], ['线性代数', 3, 76, 2.9, '必修课'], ['数据结构', 4, 90, 4.0, '必修课'],
-    ['大学英语（二）', 3, 87, 3.8, '必修课'], ['中国近现代史纲要', 2, 84, 3.5, '必修课'], ['体育（二）', 1, 86, 3.8, '必修课']
+  { term: '2023-2024-2', gpa: 4.15, rank: 36, total: 156, courses: [
+    ['高等数学（下）', 5, 84, 3.4, '必修课'], ['线性代数', 3, 76, 2.6, '必修课'], ['数据结构', 4, 90, 4.0, '必修课'],
+    ['大学英语（二）', 3, 87, 3.7, '必修课'], ['中国近现代史纲要', 2, 84, 3.4, '必修课'], ['体育（二）', 1, 86, 3.6, '必修课']
   ]},
-  { term: '2024-2025-1', gpa: 3.78, rank: 18, total: 156, courses: [
-    ['概率论与数理统计', 3, 88, 3.9, '必修课'], ['操作系统', 4, 92, 4.0, '必修课'], ['计算机网络', 4, 86, 3.8, '必修课'],
-    ['数据库原理', 3, 94, 4.0, '必修课'], ['马克思主义基本原理', 2, 81, 3.3, '必修课'], ['体育（三）', 1, 88, 3.9, '必修课']
+  { term: '2024-2025-1', gpa: 4.63, rank: 11, total: 156, courses: [
+    ['概率论与数理统计', 3, 88, 3.8, '必修课'], ['操作系统', 4, 92, 4.18, '必修课'], ['计算机网络', 4, 86, 3.6, '必修课'],
+    ['数据库原理', 3, 94, 4.36, '必修课'], ['马克思主义基本原理', 2, 81, 3.1, '必修课'], ['体育（三）', 1, 88, 3.8, '必修课']
   ]},
-  { term: '2024-2025-2', gpa: 3.85, rank: 12, total: 156, courses: [
-    ['软件工程', 3, 90, 4.0, '必修课'], ['信息安全导论', 3, 95, 4.0, '必修课'], ['密码学基础', 3, 89, 3.9, '必修课'],
-    ['Web 应用开发', 2, 96, 4.0, '专业选修课'], ['数字逻辑', 3, 79, 3.1, '必修课'], ['体育（四）', 1, 90, 4.0, '必修课']
+  { term: '2024-2025-2', gpa: 4.65, rank: 7, total: 156, courses: [
+    ['软件工程', 3, 90, 4.0, '必修课'], ['信息安全导论', 3, 95, 4.45, '必修课'], ['密码学基础', 3, 89, 3.9, '必修课'],
+    ['Web 应用开发', 2, 96, 4.55, '专业选修课'], ['数字逻辑', 3, 79, 2.9, '必修课'], ['体育（四）', 1, 90, 4.0, '必修课']
   ]}
 ];
 
@@ -1261,11 +1283,16 @@ function listFootprints(d, query) {
           dimension_ids: (dimNames || []).map((nm) => dimIds[nm]).filter(Boolean),
         }});
         n++;
-        // 演示附件：竞赛/荣誉记录附带证书图片（可预览、可进综测证明材料）
-        if (/竞赛|优秀共青团员/.test(String(title)) && status === 'finished') {
-          try {
-            handleCommand('attachment_add', { owner_id: fr.item.id, file_name: '获奖证书.png', mime: 'image/png', size: DEMO_PNG.length, data_b64: DEMO_PNG, thumb_b64: DEMO_PNG });
-          } catch {}
+        // 演示附件：按标题匹配对应证书图片（可预览、可进综测证明材料）
+        const certKey = CERT_BY_TITLE.find((p2) => p2[0].test(String(title)))?.[1];
+        if (certKey && status === 'finished') {
+          const cert = loadCert(certKey);
+          if (cert) {
+            try {
+              const att = handleCommand('attachment_add', { owner_id: fr.id, ...cert });
+              console.log('[demo-seed] 证书附件已挂到「' + title + '」:', att.item?.id || att.item?.uuid || '?');
+            } catch (e) { console.log('[demo-seed] 证书附件失败 ' + title + ':', e.message); }
+          }
         }
       }
       let sems = 0;
diff --git a/app/server/demo-certs.mjs b/app/server/demo-certs.mjs
new file mode 100644
index 0000000..01bd842
--- /dev/null
+++ b/app/server/demo-certs.mjs
@@ -0,0 +1,35 @@
+// 演示证书图片索引：demo 播种时按记录标题匹配，附加对应证书 WebP 附件。
+// 图片为 Pillow 离线绘制的获奖证书（720x508 WebP + 480px 缩略图），仅作演示数据。
+// 如需替换：直接覆盖 demo-certs/*.webp 即可，无需改代码。
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const DIR = path.join(__dirname, 'demo-certs');
+
+/**
+ * 主名（如 cert-ctf）→ 证书附件负载（attachment_add 所需格式）；文件缺失返回 undefined
+ */
+export function loadCert(assetName) {
+  try {
+    const data = fs.readFileSync(path.join(DIR, assetName + '.webp'));
+    let thumbB64 = '';
+    try { thumbB64 = fs.readFileSync(path.join(DIR, assetName + '.thumb.webp')).toString('base64'); } catch {}
+    return {
+      file_name: '获奖证书.webp', mime: 'image/webp',
+      data_b64: data.toString('base64'), thumb_b64: thumbB64, size: data.length,
+    };
+  } catch { return undefined; }
+}
+
+/** 记录标题 → 证书资源名（demo 播种时逐条匹配） */
+export const CERT_BY_TITLE = [
+  [/信息安全竞赛/, 'cert-ctf'],
+  [/数学建模/, 'cert-math'],
+  [/蓝桥杯/, 'cert-lanqiao'],
+  [/计算机设计大赛/, 'cert-cd'],
+  [/英语竞赛/, 'cert-eng'],
+  [/ACM-ICPC/, 'cert-acm'],
+  [/优秀共青团员/, 'cert-wusi'],
+];
diff --git a/app/server/demo-certs/cert-acm.thumb.webp b/app/server/demo-certs/cert-acm.thumb.webp
new file mode 100644
index 0000000..80c3b37
Binary files /dev/null and b/app/server/demo-certs/cert-acm.thumb.webp differ
diff --git a/app/server/demo-certs/cert-acm.webp b/app/server/demo-certs/cert-acm.webp
new file mode 100644
index 0000000..d291a59
Binary files /dev/null and b/app/server/demo-certs/cert-acm.webp differ
diff --git a/app/server/demo-certs/cert-cd.thumb.webp b/app/server/demo-certs/cert-cd.thumb.webp
new file mode 100644
index 0000000..6318990
Binary files /dev/null and b/app/server/demo-certs/cert-cd.thumb.webp differ
diff --git a/app/server/demo-certs/cert-cd.webp b/app/server/demo-certs/cert-cd.webp
new file mode 100644
index 0000000..b131633
Binary files /dev/null and b/app/server/demo-certs/cert-cd.webp differ
diff --git a/app/server/demo-certs/cert-ctf.thumb.webp b/app/server/demo-certs/cert-ctf.thumb.webp
new file mode 100644
index 0000000..58ae8bc
Binary files /dev/null and b/app/server/demo-certs/cert-ctf.thumb.webp differ
diff --git a/app/server/demo-certs/cert-ctf.webp b/app/server/demo-certs/cert-ctf.webp
new file mode 100644
index 0000000..b5208bd
Binary files /dev/null and b/app/server/demo-certs/cert-ctf.webp differ
diff --git a/app/server/demo-certs/cert-eng.thumb.webp b/app/server/demo-certs/cert-eng.thumb.webp
new file mode 100644
index 0000000..04be04c
Binary files /dev/null and b/app/server/demo-certs/cert-eng.thumb.webp differ
diff --git a/app/server/demo-certs/cert-eng.webp b/app/server/demo-certs/cert-eng.webp
new file mode 100644
index 0000000..8e60968
Binary files /dev/null and b/app/server/demo-certs/cert-eng.webp differ
diff --git a/app/server/demo-certs/cert-lanqiao.thumb.webp b/app/server/demo-certs/cert-lanqiao.thumb.webp
new file mode 100644
index 0000000..aa0cede
Binary files /dev/null and b/app/server/demo-certs/cert-lanqiao.thumb.webp differ
diff --git a/app/server/demo-certs/cert-lanqiao.webp b/app/server/demo-certs/cert-lanqiao.webp
new file mode 100644
index 0000000..249a36e
Binary files /dev/null and b/app/server/demo-certs/cert-lanqiao.webp differ
diff --git a/app/server/demo-certs/cert-math.thumb.webp b/app/server/demo-certs/cert-math.thumb.webp
new file mode 100644
index 0000000..09c4377
Binary files /dev/null and b/app/server/demo-certs/cert-math.thumb.webp differ
diff --git a/app/server/demo-certs/cert-math.webp b/app/server/demo-certs/cert-math.webp
new file mode 100644
index 0000000..7e62e67
Binary files /dev/null and b/app/server/demo-certs/cert-math.webp differ
diff --git a/app/server/demo-certs/cert-wusi.thumb.webp b/app/server/demo-certs/cert-wusi.thumb.webp
new file mode 100644
index 0000000..451ffe7
Binary files /dev/null and b/app/server/demo-certs/cert-wusi.thumb.webp differ
diff --git a/app/server/demo-certs/cert-wusi.webp b/app/server/demo-certs/cert-wusi.webp
new file mode 100644
index 0000000..96a1d55
Binary files /dev/null and b/app/server/demo-certs/cert-wusi.webp differ
diff --git a/app/server/seed.mjs b/app/server/seed.mjs
index 545516f..19cf450 100644
--- a/app/server/seed.mjs
+++ b/app/server/seed.mjs
@@ -1,54 +1,12 @@
-// 演示数据：仅当足迹表为空时写入，用于界面验收
-import { getDb, buildSearchText, migrateSync, uuidv7, hlcNext, DEMO_ROWS, DEMO_SEMESTERS } from './db.mjs';
+// 演示数据播种（本地开发兼容入口）
+// 与云端 demo 账号共用同一份 demo_seed 命令层逻辑（app/server/db.mjs），
+// 演示内容统一维护于 DEMO_ROWS / DEMO_SEMESTERS，竞赛/荣誉记录附带证书演示附件。
+import { handleCommand, getDb, migrateSync } from './db.mjs';
 
-const db = getDb();
-const count = db.prepare('SELECT COUNT(*) AS c FROM footprint').get().c;
-if (count > 0) {
-  console.log('已存在 ' + count + ' 条记录，跳过演示数据（如需重建请删除 app/.data 目录）');
+const r = handleCommand('demo_seed', {});
+if (!r.seeded) {
+  console.log('已存在 ' + r.footprints + ' 条记录 / ' + r.semesters + ' 个学期，跳过演示数据（如需重建请删除 app/.data 目录）');
   process.exit(0);
 }
-
-const types = Object.fromEntries(
-  db.prepare('SELECT id, name FROM footprint_type').all().map(r => [r.name, r.id])
-);
-const dims = Object.fromEntries(
-  db.prepare('SELECT id, name FROM dimension').all().map(r => [r.name, r.id])
-);
-
-// [type, title, role, level, grade, organizer, start, end, status, desc, result, tags, dims, extras, metrics]
-// 数据统一维护在 ./db.mjs（DEMO_ROWS / DEMO_SEMESTERS）
-
-const ins = db.prepare(`INSERT INTO footprint (type_id, title, role, level, award_grade, organizer,
-  start_date, end_date, status, description, result, tags, search_text, extras, metrics)
-  VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`);
-const setDim = db.prepare('INSERT OR IGNORE INTO footprint_dimension (footprint_id, dimension_id) VALUES (?,?)');
-
-for (const [t, title, role, level, grade, organizer, start, end, status, desc, result, tags, dimNames, extras, metrics] of DEMO_ROWS) {
-  const search = buildSearchText(title, desc, result, tags, extras);
-  const r = ins.run(types[t], title, role, level, grade, organizer, start, end, status, desc, result,
-    JSON.stringify(tags), search, JSON.stringify(extras), JSON.stringify(metrics));
-  const id = Number(r.lastInsertRowid);
-  for (const name of dimNames) {
-    if (dims[name]) setDim.run(id, dims[name]);
-  }
-}
-
-console.log('已写入 ' + DEMO_ROWS.length + ' 条演示记录');
-
-// ---------- 学年学科成绩演示 ----------
-const semIns = db.prepare('INSERT INTO semester (term, gpa, rank, total_students, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?)');
-const couIns = db.prepare('INSERT INTO course_grade (semester_id, course_name, credit, score, grade_point, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?)');
-
-
-
-for (const s of DEMO_SEMESTERS) {
-  const h1 = hlcNext(db);
-  const sid = Number(semIns.run(s.term, s.gpa, s.rank, s.total, uuidv7(), h1, 'seed').lastInsertRowid);
-  for (const [name, credit, score, gp] of s.courses) {
-    couIns.run(sid, name, credit, score, gp, uuidv7(), hlcNext(db), 'seed');
-  }
-}
-console.log('已写入 ' + DEMO_SEMESTERS.length + ' 个学期、' + DEMO_SEMESTERS.reduce((a, s) => a + s.courses.length, 0) + ' 门课程成绩');
-
 migrateSync(getDb());
-console.log('同步元数据（uuid/hlc/origin）已回填');
+console.log('演示数据已写入：足迹 ' + r.footprints + ' 条、学期成绩 ' + r.semesters + ' 个（竞赛/荣誉记录附带证书演示附件）');