fix(ui): improve background handling and PWA update prompts

- Add adaptive solid color background support for dark/light themes.
- Replace mesh gradient with semi-transparent blurred background images.
- Fix background scrolling issue on mobile browsers.
- Remove borders from specific cards for consistent UI styling.
- Prevent caching of PWA service worker files in Nginx.
- Introduce interactive toast prompt for PWA updates instead of silent refresh.

vite-frontend/nginx.conf

@@ -43,6 +43,14 @@ http {
         root /usr/share/nginx/html;
         index index.html;
 
+        # PWA 和 Service Worker 不缓存
+        location ~* (sw\.js|service-worker\.js|workbox-.*\.js|manifest\.webmanifest)$ {
+            add_header Cache-Control "no-cache, no-store, must-revalidate";
+            add_header Pragma "no-cache";
+            add_header Expires "0";
+            try_files $uri =404;
+        }
+
         # 静态文件缓存
         location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$ {
             expires 30d;

vite-frontend/src/App.tsx

@@ -95,11 +95,28 @@ function App() {
     const updateBg = () => {
       const customBg = siteConfig.app_bg_image;
       if (customBg) {
-        document.documentElement.style.setProperty("--custom-bg-image", `url(${customBg})`);
+        if (customBg === "theme") {
-        document.documentElement.classList.add("has-custom-bg");
+          document.documentElement.style.removeProperty("--custom-bg-image");
+          document.documentElement.style.removeProperty("--custom-bg-color");
+          document.documentElement.classList.add("has-theme-bg");
+          document.documentElement.classList.remove("has-custom-bg");
+        } else if (customBg.startsWith("http") || customBg.startsWith("data:") || customBg.startsWith("/") || customBg.startsWith("blob:")) {
+          document.documentElement.style.setProperty("--custom-bg-image", `url(${customBg})`);
+          document.documentElement.style.setProperty("--custom-bg-color", "transparent");
+          document.documentElement.classList.add("has-custom-bg");
+          document.documentElement.classList.remove("has-theme-bg");
+        } else {
+          // Assume solid color like "#ffffff", "white", etc.
+          document.documentElement.style.setProperty("--custom-bg-image", "none");
+          document.documentElement.style.setProperty("--custom-bg-color", customBg);
+          document.documentElement.classList.add("has-custom-bg");
+          document.documentElement.classList.remove("has-theme-bg");
+        }
       } else {
         document.documentElement.style.removeProperty("--custom-bg-image");
+        document.documentElement.style.removeProperty("--custom-bg-color");
         document.documentElement.classList.remove("has-custom-bg");
+        document.documentElement.classList.remove("has-theme-bg");
       }
     };
     updateBg();

vite-frontend/src/components/theme-settings.tsx

@@ -54,7 +54,7 @@ export const ThemeSettings: React.FC = () => {
   };
 
   return (
-    <Card className="border border-gray-200 dark:border-gray-700">
+    <Card className="shadow-md">
       <CardBody className="p-6">
         <h2 className="text-lg font-medium text-gray-900 dark:text-white mb-5">
           主题设置

vite-frontend/src/main.tsx

@@ -1,12 +1,42 @@
 import ReactDOM from "react-dom/client";
 import { BrowserRouter } from "react-router-dom";
 import { registerSW } from "virtual:pwa-register";
+import toast from "react-hot-toast";
 
 import App from "./App.tsx";
 import { Provider } from "./provider.tsx";
 import "@/styles/globals.css";
 
-registerSW({ immediate: true });
+const updateSW = registerSW({
+  immediate: true,
+  onNeedRefresh() {
+    toast(
+      (t) => (
+        <div className="flex flex-col gap-3">
+          <span className="text-sm font-medium text-foreground">发现新版本，是否立即刷新以应用更新？</span>
+          <div className="flex gap-2 justify-end">
+            <button
+              className="px-3 py-1.5 text-xs font-medium bg-primary text-primary-foreground hover:bg-primary/90 rounded-md transition-colors"
+              onClick={() => {
+                updateSW(true);
+                toast.dismiss(t.id);
+              }}
+            >
+              刷新
+            </button>
+            <button
+              className="px-3 py-1.5 text-xs font-medium bg-default-200 text-default-700 hover:bg-default-300 rounded-md transition-colors"
+              onClick={() => toast.dismiss(t.id)}
+            >
+              稍后
+            </button>
+          </div>
+        </div>
+      ),
+      { duration: Infinity, position: "bottom-right" }
+    );
+  },
+});
 
 ReactDOM.createRoot(document.getElementById("root")!).render(
   <BrowserRouter>

vite-frontend/src/pages/config.tsx

@@ -621,10 +621,13 @@ export default function ConfigPage() {
 
   const renderBgImageUploader = () => {
     const bgImage = configs["app_bg_image"] || "";
+    const isImage = bgImage.startsWith("http") || bgImage.startsWith("data:") || bgImage.startsWith("/") || bgImage.startsWith("blob:");
+    const isTheme = bgImage === "theme";
+    const isSolidColor = bgImage && !isImage && !isTheme;
     
     return (
       <div className="flex flex-col gap-4 w-full">
-        <div className="flex items-center gap-4">
+        <div className="flex flex-wrap items-center gap-4">
           <input
             type="file"
             accept="image/*"
@@ -638,7 +641,23 @@ export default function ConfigPage() {
             onPress={() => bgImageFileInputRef.current?.click()}
             isLoading={bgImageUploading}
           >
-            选择图片
+            上传图片
+          </Button>
+          <Button
+            color="secondary"
+            variant="flat"
+            onPress={() => handleConfigChange("app_bg_image", "theme")}
+            isDisabled={bgImageUploading || isTheme}
+          >
+            自适应纯色 (跟随深色模式)
+          </Button>
+          <Button
+            color="default"
+            variant="flat"
+            onPress={() => handleConfigChange("app_bg_image", "#ffffff")}
+            isDisabled={bgImageUploading || bgImage === "#ffffff"}
+          >
+            白色纯色
           </Button>
           {bgImage && (
             <Button
@@ -647,11 +666,12 @@ export default function ConfigPage() {
               onPress={() => handleConfigChange("app_bg_image", "")}
               isDisabled={bgImageUploading}
             >
-              清除背景
+              恢复默认
             </Button>
           )}
         </div>
-        {bgImage && (
+        
+        {bgImage && isImage && (
           <div className="relative rounded-xl overflow-hidden border border-divider">
             <img
               src={bgImage}
@@ -663,6 +683,23 @@ export default function ConfigPage() {
             </div>
           </div>
         )}
+
+        {bgImage && isTheme && (
+          <div className="relative rounded-xl border border-divider bg-background h-32 flex items-center justify-center">
+            <span className="text-foreground text-sm font-medium">当前为自适应纯色背景</span>
+          </div>
+        )}
+
+        {bgImage && isSolidColor && (
+          <div 
+            className="relative rounded-xl border border-divider h-32 flex items-center justify-center" 
+            style={{ backgroundColor: bgImage }}
+          >
+            <span className="text-gray-500 bg-white/80 dark:bg-black/80 px-2 py-1 rounded text-sm font-medium border border-gray-200 dark:border-gray-800 shadow-sm">
+              纯色背景 ({bgImage})
+            </span>
+          </div>
+        )}
       </div>
     );
   };

vite-frontend/src/pages/limit.tsx

@@ -327,7 +327,7 @@ export default function LimitPage() {
         <StaggerList className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 2xl:grid-cols-5 gap-4">
           {filteredRules.map((rule) => (
             <StaggerItem key={rule.id}>
-              <Card className="shadow-sm border border-gray-200 dark:border-gray-700 overflow-hidden h-full">
+              <Card className="shadow-sm overflow-hidden h-full">
                 <CardHeader className="pb-2 md:pb-2">
                   <div className="flex justify-between items-start w-full">
                     <div>
@@ -413,7 +413,7 @@ export default function LimitPage() {
         )
       ) : (
         /* 空状态 */
-        <Card className="shadow-sm border border-gray-200 dark:border-gray-700 bg-default-50/50">
+        <Card className="shadow-sm bg-default-50/50">
           <CardBody className="text-center py-20 flex flex-col items-center justify-center min-h-[240px]">
             <h3 className="text-xl font-medium text-foreground tracking-tight mb-2">
               暂无限速规则

vite-frontend/src/styles/globals.css

@@ -227,24 +227,56 @@ body {
 }
 
 .bg-mesh-gradient {
-  background: radial-gradient(at 0% 0%, #ff9a9e 0%, transparent 50%),
-              radial-gradient(at 100% 0%, #fecfef 0%, transparent 50%),
-              radial-gradient(at 100% 100%, #c2e9fb 0%, transparent 50%),
-              radial-gradient(at 0% 100%, #a1c4fd 0%, transparent 50%);
   background-color: #f2f2f7;
+  position: relative;
+  z-index: 0;
 }
 
-.dark .bg-mesh-gradient {
+.bg-mesh-gradient::before {
-  background: radial-gradient(at 0% 0%, #4a2b30 0%, transparent 50%),
+  content: "";
-              radial-gradient(at 100% 0%, #493b45 0%, transparent 50%),
+  position: fixed;
-              radial-gradient(at 100% 100%, #354756 0%, transparent 50%),
+  top: 0;
-              radial-gradient(at 0% 100%, #2f394f 0%, transparent 50%);
+  left: 0;
-  background-color: #1c1c1e;
+  right: 0;
+  bottom: 0;
+  z-index: -1;
+  pointer-events: none;
+  background: url('https://images.unsplash.com/photo-1618005182384-a83a8bd57fbe?q=80&w=2564&auto=format&fit=crop') no-repeat center center;
+  background-size: cover;
+}
+
+:root.dark .bg-mesh-gradient {
+  background-color: #0b1020;
+}
+
+.dark .bg-mesh-gradient::before {
+  background: url('https://images.unsplash.com/photo-1557682250-33bd709cbe85?q=80&w=2564&auto=format&fit=crop') no-repeat center center;
+  background-size: cover;
+}
+
+:root.has-theme-bg .bg-mesh-gradient {
+  background-image: none !important;
+  background-color: #f6f7fb !important;
+}
+
+:root.dark.has-theme-bg .bg-mesh-gradient {
+  background-color: #0b1020 !important;
+}
+
+:root.has-theme-bg .bg-mesh-gradient::before {
+  background-image: none !important;
 }
 
 :root.has-custom-bg .bg-mesh-gradient {
-  background: var(--custom-bg-image) no-repeat center center fixed !important;
+  background-image: none !important;
+  background-color: var(--custom-bg-color, transparent) !important;
+}
+
+:root.has-custom-bg .bg-mesh-gradient::before {
+  background-image: var(--custom-bg-image, none) !important;
   background-size: cover !important;
+  background-position: center center !important;
+  background-repeat: no-repeat !important;
 }
 
 @layer utilities {

vite-frontend/vite.config.ts

@@ -8,7 +8,7 @@ export default defineConfig({
   plugins: [
     react(),
     VitePWA({
-      registerType: "autoUpdate",
+      registerType: "prompt",
       injectRegister: "auto",
       includeAssets: ["favicon.ico", "apple-touch-icon.png"],
       manifest: {