docs: switch to docs layout and apply black theme (#6533)

* feat: add Gemini 3.1 models

- Add gemini-3.1-pro-preview (released February 19, 2026)
- Add gemini-3.1-flash-lite-preview (released March 3, 2026)

Both models support:
- 1M context window
- 64k max response
- Vision
- Tool choice

* docs: switch to docs layout and apply black theme

- Change layout from notebook to docs
- Update logo to icon + text format
- Apply fumadocs black theme
- Simplify global.css (keep only navbar and TOC styles)
- Fix icon components to properly accept className props
- Add mobile text overflow handling
- Update Node engine requirement to >=20.x

* doc

* doc

* lock

* fix: ts

* doc

* doc

---------

Co-authored-by: archer <archer@archerdeMac-mini.local>
Co-authored-by: archer <545436317@qq.com>

document/app/[lang]/docs/layout.tsx

@@ -1,18 +1,17 @@
 import { type ReactNode } from 'react';
 import { source } from '@/lib/source';
-import { DocsLayout } from 'fumadocs-ui/layouts/notebook';
+import { DocsLayout } from 'fumadocs-ui/layouts/docs';
 import { baseOptions } from '@/app/layout.config';
 import { t, getLocalizedPath, i18n } from '@/lib/i18n';
-import LogoLight from '@/components/docs/logo';
-import LogoDark from '@/components/docs/logoDark';
 import '@/app/global.css';
 import { CustomSidebarComponents } from '@/components/sideBar';
 import { SidebarKeepOpen } from '@/components/sidebarKeepOpen';
+import { SidebarScrollFix } from '@/components/sidebarScrollFix';
 import FeishuLogoLight from '@/components/docs/feishuLogoLIght';
 import FeishuLogoDark from '@/components/docs/feishuLogoDark';
 import GithubLogoLight from '@/components/docs/githubLogoLight';
 import GithubLogoDark from '@/components/docs/githubLogoDark';
-import { BookOpen, Code, Lightbulb, CircleHelp, Scale, History, Server } from 'lucide-react';
+import { BookOpen, Code, Lightbulb, CircleHelp, Server } from 'lucide-react';
 
 export default async function Layout({
   params,
@@ -57,51 +56,6 @@ export default async function Layout({
   return (
     <DocsLayout
       {...baseOptions(lang)}
-      nav={{
-        title: (
-          <div className="flex flex-row items-center gap-2 h-14 ml-1">
-            <div className="block dark:hidden">
-              <LogoLight className="w-48 h-auto" />
-            </div>
-            <div className="hidden dark:block">
-              <LogoDark className="w-48 h-auto" />
-            </div>
-          </div>
-        ),
-        mode: 'top'
-      }}
-      links={[
-        {
-          type: 'icon',
-          icon: (
-            <div className="flex flex-row items-center gap-2">
-              <div className="block dark:hidden">
-                <FeishuLogoLight />
-              </div>
-              <div className="hidden dark:block">
-                <FeishuLogoDark />
-              </div>
-            </div>
-          ),
-          url: 'https://oss.laf.run/otnvvf-imgs/fastgpt-feishu1.png',
-          text: '飞书群'
-        },
-        {
-          type: 'icon',
-          icon: (
-            <div className="flex flex-row items-center gap-2">
-              <div className="block dark:hidden">
-                <GithubLogoLight />
-              </div>
-              <div className="hidden dark:block">
-                <GithubLogoDark />
-              </div>
-            </div>
-          ),
-          url: 'https://github.com/labring/FastGPT',
-          text: 'github'
-        }
-      ]}
       tree={source.pageTree[lang] || source.pageTree[i18n.defaultLanguage]}
       searchToggle={{
         enabled: true
@@ -111,9 +65,23 @@ export default async function Layout({
         collapsible: false,
         components: CustomSidebarComponents
       }}
-      tabMode="sidebar"
+      links={[
+        {
+          type: 'icon',
+          icon: <FeishuLogoLight className="block dark:hidden size-5" />,
+          url: 'https://oss.laf.run/otnvvf-imgs/fastgpt-feishu1.png',
+          text: '飞书群'
+        },
+        {
+          type: 'icon',
+          icon: <GithubLogoLight className="block dark:hidden size-5" />,
+          url: 'https://github.com/labring/FastGPT',
+          text: 'github'
+        }
+      ]}
     >
       <SidebarKeepOpen tabUrls={tabUrls} />
+      <SidebarScrollFix />
       {children}
     </DocsLayout>
   );