feat(docs): float RainYun sponsor card on doc pages

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

@@ -2,6 +2,7 @@ import type { ReactNode } from "react";
 import { DocsLayout } from "fumadocs-ui/layouts/docs";
 import { RootProvider } from "fumadocs-ui/provider/next";
 import { DocsSidebarFooter, DocsSidebarLanguageButton } from "@/components/DocsSidebarFooter";
+import { FloatingSponsorCard } from "@/components/FloatingSponsorCard";
 import { StaticSearchDialog } from "@/components/StaticSearchDialog";
 import { i18nUI, resolveLang } from "@/lib/i18n";
 import { source } from "@/lib/source";
@@ -37,6 +38,7 @@ export default async function Layout({ params, children }: { params: Promise<{ l
         }}
       >
         {children}
+        <FloatingSponsorCard lang={locale} />
       </DocsLayout>
     </RootProvider>
   );

docs/app/global.css

@@ -22,6 +22,23 @@
     opacity 0.22s ease;
 }
 
+/* 文档页右下角赞助悬浮卡片入场动画 */
+
+@keyframes sponsor-card-in {
+  from {
+    opacity: 0;
+    transform: translateY(8px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
+
+.sponsor-card-in {
+  animation: sponsor-card-in 0.3s ease-out both;
+}
+
 @theme {
   --color-landing-bg: #161616;
   --color-landing-ink: #ededf0;

docs/components/FloatingSponsorCard.tsx

@@ -0,0 +1,77 @@
+"use client";
+
+import { X } from "lucide-react";
+import { useEffect, useState } from "react";
+
+const DISMISS_STORAGE_KEY = "dbx.docs.sponsorCard.dismissedAt";
+// 关闭 7 天后重新出现
+const RESURFACE_MS = 7 * 24 * 60 * 60 * 1000;
+
+const RAINYUN_URL = "https://www.rainyun.com/MTE5Mjc4Ng==_";
+
+const COPY = {
+  cn: {
+    badge: "赞助商",
+    tagline: "云服务器 · 游戏云 · 物理服务器",
+    closeLabel: "关闭赞助卡片",
+  },
+  en: {
+    badge: "Sponsor",
+    tagline: "Cloud servers, game hosting & bare metal",
+    closeLabel: "Dismiss sponsor card",
+  },
+} as const;
+
+export function FloatingSponsorCard({ lang }: { lang: string }) {
+  const [visible, setVisible] = useState(false);
+
+  useEffect(() => {
+    try {
+      const dismissedAt = Number(window.localStorage.getItem(DISMISS_STORAGE_KEY));
+      if (!Number.isFinite(dismissedAt) || Date.now() - dismissedAt > RESURFACE_MS) {
+        setVisible(true);
+      }
+    } catch {
+      setVisible(true);
+    }
+  }, []);
+
+  if (!visible) return null;
+
+  const dismiss = () => {
+    setVisible(false);
+    try {
+      window.localStorage.setItem(DISMISS_STORAGE_KEY, String(Date.now()));
+    } catch {
+      // localStorage 不可用时按本次会话关闭处理
+    }
+  };
+
+  const t = lang === "cn" ? COPY.cn : COPY.en;
+
+  return (
+    <aside
+      aria-label={t.badge}
+      className="sponsor-card-in fixed bottom-4 right-4 z-30 w-52 rounded-xl border border-fd-border bg-fd-card/95 p-2.5 shadow-lg backdrop-blur"
+    >
+      <div className="flex items-center justify-between">
+        <span className="text-[10px] font-medium tracking-wide text-fd-muted-foreground">{t.badge}</span>
+        <button
+          type="button"
+          aria-label={t.closeLabel}
+          onClick={dismiss}
+          className="rounded-md p-1 text-fd-muted-foreground transition-colors hover:bg-fd-accent hover:text-fd-foreground"
+        >
+          <X className="size-3.5" />
+        </button>
+      </div>
+      <a href={RAINYUN_URL} target="_blank" rel="nofollow sponsored noopener noreferrer" className="group mt-1.5 block">
+        {/* 品牌图为白底，暗色主题下需显式白底容器承载 */}
+        <span className="block overflow-hidden rounded-lg bg-white ring-1 ring-black/5 transition-shadow group-hover:ring-black/15">
+          <img src="/sponsors/rainyun-card.png" alt="RainYun" width={400} height={160} className="h-auto w-full" />
+        </span>
+        <span className="mt-1 block text-center text-xs text-fd-muted-foreground">{t.tagline}</span>
+      </a>
+    </aside>
+  );
+}