diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f1c68f..df9d25b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@
 
 ## Unreleased
 
+- Mermaid 图表采用更清晰的科研配色与更精致的图框，新生成的流程图还会按数据、处理、判断、结果等角色使用协调的语义色，减少单调的灰白图。
+
 - 管理后台总览按“当前运行”和“运营资源”重新组织，执行容量改为精简摘要并可从右侧详情面板查看队列、容器、用户占用与宿主资源，异常状态和近期指标也更容易识别。
 
 ## 0.70.0 — 2026-09-02
@@ -20,8 +22,6 @@
 
 - 专业软件节点启用完整的新管理界面，节点状态、首次注册、软件环境、本机任务、ANSYS 验收和数据目录迁移均可直接管理；应用图标、导航、状态提示和窄窗口布局也更清晰，关闭窗口后仍会继续在托盘运行。
 
-- 删除已发布文件后会释放个人存储配额；管理员可分别查看用户当前文件、隐藏回收站及物理总占用。
-
 ## 0.69.1 — 2026-08-27
 
 - 专业软件任务的进度与结果改为在当前对话左侧集中堆叠，不再用多条结果消息打断正文；可直接打开 Blender 等软件的多张预览，手机端从“软件结果”入口统一查看。
diff --git a/core/agent_builder.py b/core/agent_builder.py
index 078dbda..1ecbec6 100644
--- a/core/agent_builder.py
+++ b/core/agent_builder.py
@@ -161,6 +161,14 @@ _HOST_ENV_BLOCK = """\
 ## 运行环境(本地 host)
 `shell` 走的是 **Windows cmd.exe**(非 bash):避免 unix-only flag,`mkdir -p` 不识别 → 用 `run_python` 的 `os.makedirs(..., exist_ok=True)` 建目录;复杂管道/重定向用 run_python 更稳。"""
 
+_MERMAID_STYLE_BLOCK = """\
+
+## Mermaid 视觉规范
+生成 Mermaid 图时默认采用**克制的语义配色**,不要输出全灰单色图,也不要随机彩虹色:
+- 流程图 / 架构图用 `classDef` 按角色分组,通常 3–5 色足够:输入/数据用蓝色,处理/模块用青绿色,判断/风险用橙色,结果/成功用绿色,异常用红色;同类节点保持同色。
+- 使用浅色填充、较深描边与高对比深色文字,线条颜色统一;分组框比节点更淡,避免大面积高饱和背景。
+- 颜色服务于信息层级;若用户指定品牌色、黑白打印或已有 `classDef` / `style` 规则,优先遵循用户设置,不要覆盖。"""
+
 
 def load_config() -> dict:
     return yaml.safe_load((ROOT / "config" / "agent.yaml").read_text(encoding="utf-8")) or {}
@@ -363,6 +371,7 @@ def _build_system_prompt(
     is_docker = os.getenv("ZCBOT_SANDBOX_BACKEND", "host").lower() == "docker"
     # 运行环境段紧跟模板(平台/网络是基础事实,放前面);general_v1 的「平台」段指向这里。
     prompt += _CONTAINER_ENV_BLOCK if is_docker else _HOST_ENV_BLOCK
+    prompt += _MERMAID_STYLE_BLOCK
     if skills.skills:
         prompt += f"\n\n## 可用 skill (用 load_skill 加载完整指引)\n{skills.discovery_block()}"
     # .memory/ 在 agent 视角下的可写路径:docker 给容器路径,host 给宿主绝对路径。
diff --git a/tests/frontend_markdown_guard.test.mjs b/tests/frontend_markdown_guard.test.mjs
index d7306f2..aa33c7f 100644
--- a/tests/frontend_markdown_guard.test.mjs
+++ b/tests/frontend_markdown_guard.test.mjs
@@ -78,6 +78,11 @@ test("renders completed mermaid blocks with strict local configuration", async (
   assert.equal(calls.initialize.length, 1);
   assert.equal(calls.initialize[0].securityLevel, "strict");
   assert.equal(calls.initialize[0].startOnLoad, false);
+  assert.equal(calls.initialize[0].theme, "base");
+  assert.equal(calls.initialize[0].themeVariables.primaryColor, "#eaf2ff");
+  assert.equal(calls.initialize[0].themeVariables.secondaryColor, "#e8f7f3");
+  assert.equal(calls.initialize[0].themeVariables.tertiaryColor, "#fff4df");
+  assert.equal(calls.initialize[0].themeVariables.pie5, "#d96c75");
   assert.equal(calls.render[0].source, "flowchart LR\nA --> B");
   assert.equal(fixture.pre.replacement.className, "mermaid-diagram");
   assert.equal(fixture.pre.replacement.children[0].innerHTML, "<svg viewBox='0 0 10 10'></svg>");
diff --git a/tests/test_system_prompt_paths.py b/tests/test_system_prompt_paths.py
index 8ce8b81..5cb28e1 100644
--- a/tests/test_system_prompt_paths.py
+++ b/tests/test_system_prompt_paths.py
@@ -75,6 +75,15 @@ class TestSystemPromptPaths(unittest.TestCase):
         self.assertIn(str(wd), prompt)
         self.assertNotIn("/workspace/数据资源展示", prompt)
 
+    def test_mermaid_visual_guidance_is_backend_independent(self):
+        for backend in ("docker", "host"):
+            with self.subTest(backend=backend):
+                prompt, _, _ = _build(backend)
+                self.assertIn("## Mermaid 视觉规范", prompt)
+                self.assertIn("`classDef` 按角色分组", prompt)
+                self.assertIn("不要输出全灰单色图", prompt)
+                self.assertIn("用户指定品牌色", prompt)
+
     def test_rename_guard_only_when_tool_is_available(self):
         interactive, _, _ = _build("docker", allow_rename=True)
         scheduled, _, _ = _build("docker", allow_rename=False)
diff --git a/web/static/js/markdown.js b/web/static/js/markdown.js
index c79096e..f923eb5 100644
--- a/web/static/js/markdown.js
+++ b/web/static/js/markdown.js
@@ -11,7 +11,53 @@ const MERMAID_CONFIG = Object.freeze({
   startOnLoad: false,
   securityLevel: "strict",
   suppressErrorRendering: true,
-  theme: "neutral",
+  // A restrained scientific palette. Author-defined classDef/style rules still
+  // take precedence, while unstyled diagrams get a consistent visual baseline.
+  theme: "base",
+  themeVariables: Object.freeze({
+    background: "#ffffff",
+    primaryColor: "#eaf2ff",
+    primaryTextColor: "#17324d",
+    primaryBorderColor: "#5b8fc9",
+    secondaryColor: "#e8f7f3",
+    secondaryTextColor: "#163c35",
+    secondaryBorderColor: "#4f9f8d",
+    tertiaryColor: "#fff4df",
+    tertiaryTextColor: "#594018",
+    tertiaryBorderColor: "#d79a3b",
+    lineColor: "#60758a",
+    textColor: "#25384a",
+    mainBkg: "#eaf2ff",
+    secondBkg: "#e8f7f3",
+    border1: "#5b8fc9",
+    border2: "#4f9f8d",
+    arrowheadColor: "#60758a",
+    clusterBkg: "#f7f9fc",
+    clusterBorder: "#b9c8d8",
+    actorBkg: "#eaf2ff",
+    actorBorder: "#5b8fc9",
+    actorTextColor: "#17324d",
+    actorLineColor: "#8ca0b3",
+    signalColor: "#536b82",
+    signalTextColor: "#25384a",
+    labelBoxBkgColor: "#f7f9fc",
+    labelBoxBorderColor: "#b9c8d8",
+    labelTextColor: "#25384a",
+    loopTextColor: "#25384a",
+    noteBkgColor: "#fff4df",
+    noteBorderColor: "#d79a3b",
+    noteTextColor: "#594018",
+    activationBkgColor: "#d9eee9",
+    activationBorderColor: "#4f9f8d",
+    pie1: "#4f7cac",
+    pie2: "#5ca89a",
+    pie3: "#e4a64a",
+    pie4: "#a879b2",
+    pie5: "#d96c75",
+    pie6: "#6d9dc5",
+    pie7: "#84b59f",
+    pie8: "#d8b365",
+  }),
   maxTextSize: 50000,
   maxEdges: 500,
   fontFamily: '-apple-system, "Segoe UI", "Microsoft YaHei", sans-serif',
diff --git a/web/static/ui.css b/web/static/ui.css
index ebbb8aa..1b53478 100644
--- a/web/static/ui.css
+++ b/web/static/ui.css
@@ -442,11 +442,12 @@ header .who {
 
 .mermaid-diagram {
   margin: 14px 0;
-  padding: 14px;
+  padding: 18px;
   overflow-x: auto;
-  border: 1px solid var(--border-soft);
-  border-radius: var(--r-lg);
-  background: #ffffff;
+  border: 1px solid #dce6f2;
+  border-radius: var(--r-xl);
+  background: linear-gradient(145deg, #ffffff 0%, #f8fbff 100%);
+  box-shadow: 0 6px 22px rgba(50, 79, 108, 0.08);
 }
 
 .mermaid-viewport {
@@ -458,6 +459,7 @@ header .who {
   max-width: 100%;
   height: auto;
   margin: 0 auto;
+  filter: drop-shadow(0 2px 3px rgba(38, 61, 82, 0.06));
 }
 
 .mermaid-notice {