fix: 暗色主题全面优化 - 滚动条、颜色适配、dark:伪类修复

- 添加全局暗色滚动条样式 (globals.css)
- 修复 channels/subscriptions 页面 dark: 伪类无效的bug (改用 isDark)
- 修复 RefundDialog 暗色下退款金额、disabled 按钮颜色
- 修复 admin OrderTable 暗色下缺少背景色
- 统一所有 admin 页面 text-gray-500 为 slate 色系
- 修复 UserSubscriptions 续费按钮暗色适配
- 修复日期标签文字缺少暗色颜色类
- MainTabs 暗色容器改用 slate-900 提升对比度
- OpenAI 默认模型区域暗色边框透明度提升
- 更新 README 文档

src/app/admin/channels/page.tsx

@@ -328,7 +328,7 @@ function ChannelsContent() {
       <div className={`flex min-h-screen items-center justify-center p-4 ${isDark ? 'bg-slate-950' : 'bg-slate-50'}`}>
         <div className="text-center text-red-500">
           <p className="text-lg font-medium">{t.missingToken}</p>
-          <p className="mt-2 text-sm text-gray-500">{t.missingTokenHint}</p>
+          <p className={`mt-2 text-sm ${isDark ? 'text-slate-400' : 'text-slate-500'}`}>{t.missingTokenHint}</p>
         </div>
       </div>
     );
@@ -721,13 +721,13 @@ function ChannelsContent() {
                     </td>
                     <td className="px-4 py-3 text-center">
                       {channel.groupExists ? (
-                        <span className="inline-flex h-5 w-5 items-center justify-center rounded-full bg-emerald-100 text-emerald-600 dark:bg-emerald-900/40 dark:text-emerald-400">
+                        <span className={`inline-flex h-5 w-5 items-center justify-center rounded-full ${isDark ? 'bg-emerald-900/40 text-emerald-400' : 'bg-emerald-100 text-emerald-600'}`}>
                           <svg className="h-3.5 w-3.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2.5}>
                             <path strokeLinecap="round" strokeLinejoin="round" d="M5 13l4 4L19 7" />
                           </svg>
                         </span>
                       ) : (
-                        <span className="inline-flex h-5 w-5 items-center justify-center rounded-full bg-red-100 text-red-600 dark:bg-red-900/40 dark:text-red-400">
+                        <span className={`inline-flex h-5 w-5 items-center justify-center rounded-full ${isDark ? 'bg-red-900/40 text-red-400' : 'bg-red-100 text-red-600'}`}>
                           <svg className="h-3.5 w-3.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2.5}>
                             <path strokeLinecap="round" strokeLinejoin="round" d="M6 18L18 6M6 6l12 12" />
                           </svg>
@@ -997,7 +997,7 @@ function ChannelsContent() {
                         disabled={alreadyImported}
                         checked={syncSelected.has(group.id)}
                         onChange={() => toggleSyncGroup(group.id)}
-                        className="mt-0.5 h-4 w-4 rounded border-slate-300 text-indigo-500 focus:ring-indigo-500"
+                        className={`mt-0.5 h-4 w-4 rounded text-indigo-500 focus:ring-indigo-500 ${isDark ? 'border-slate-600 bg-slate-700' : 'border-slate-300'}`}
                       />
                       <div className="flex-1 min-w-0">
                         <div className="flex items-center gap-2">
@@ -1061,7 +1061,7 @@ function ChannelsPageFallback() {
 
   return (
     <div className="flex min-h-screen items-center justify-center">
-      <div className="text-gray-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
+      <div className="text-slate-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
     </div>
   );
 }

src/app/admin/dashboard/page.tsx

@@ -103,7 +103,7 @@ function DashboardContent() {
       <div className={`flex min-h-screen items-center justify-center p-4 ${isDark ? 'bg-slate-950' : 'bg-slate-50'}`}>
         <div className="text-center text-red-500">
           <p className="text-lg font-medium">{text.missingToken}</p>
-          <p className="mt-2 text-sm text-gray-500">{text.missingTokenHint}</p>
+          <p className={`mt-2 text-sm ${isDark ? 'text-slate-400' : 'text-slate-500'}`}>{text.missingTokenHint}</p>
         </div>
       </div>
     );
@@ -185,7 +185,7 @@ function DashboardPageFallback() {
 
   return (
     <div className="flex min-h-screen items-center justify-center">
-      <div className="text-gray-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
+      <div className="text-slate-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
     </div>
   );
 }

src/app/admin/orders/page.tsx

@@ -162,7 +162,7 @@ function AdminContent() {
       <div className={`flex min-h-screen items-center justify-center p-4 ${isDark ? 'bg-slate-950' : 'bg-slate-50'}`}>
         <div className="text-center text-red-500">
           <p className="text-lg font-medium">{text.missingToken}</p>
-          <p className="mt-2 text-sm text-gray-500">{text.missingTokenHint}</p>
+          <p className={`mt-2 text-sm ${isDark ? 'text-slate-400' : 'text-slate-500'}`}>{text.missingTokenHint}</p>
         </div>
       </div>
     );
@@ -335,7 +335,7 @@ function AdminPageFallback() {
 
   return (
     <div className="flex min-h-screen items-center justify-center">
-      <div className="text-gray-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
+      <div className="text-slate-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
     </div>
   );
 }

src/app/admin/page.tsx

@@ -103,7 +103,7 @@ function DashboardContent() {
       <div className={`flex min-h-screen items-center justify-center p-4 ${isDark ? 'bg-slate-950' : 'bg-slate-50'}`}>
         <div className="text-center text-red-500">
           <p className="text-lg font-medium">{text.missingToken}</p>
-          <p className="mt-2 text-sm text-gray-500">{text.missingTokenHint}</p>
+          <p className={`mt-2 text-sm ${isDark ? 'text-slate-400' : 'text-slate-500'}`}>{text.missingTokenHint}</p>
         </div>
       </div>
     );
@@ -185,7 +185,7 @@ function DashboardPageFallback() {
 
   return (
     <div className="flex min-h-screen items-center justify-center">
-      <div className="text-gray-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
+      <div className="text-slate-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
     </div>
   );
 }

src/app/admin/subscriptions/page.tsx

@@ -596,7 +596,7 @@ function SubscriptionsContent() {
       <div className={`flex min-h-screen items-center justify-center p-4 ${isDark ? 'bg-slate-950' : 'bg-slate-50'}`}>
         <div className="text-center text-red-500">
           <p className="text-lg font-medium">{t.missingToken}</p>
-          <p className="mt-2 text-sm text-gray-500">{t.missingTokenHint}</p>
+          <p className={`mt-2 text-sm ${isDark ? 'text-slate-400' : 'text-slate-500'}`}>{t.missingTokenHint}</p>
         </div>
       </div>
     );
@@ -920,7 +920,7 @@ function SubscriptionsContent() {
                           <>
                             <div>
                               <span className={isDark ? 'text-slate-500' : 'text-slate-400'}>/v1/messages 调度</span>
-                              <div className={['mt-0.5 text-xs font-medium', plan.groupAllowMessagesDispatch ? 'text-green-600 dark:text-green-400' : isDark ? 'text-slate-400' : 'text-slate-500'].join(' ')}>
+                              <div className={['mt-0.5 text-xs font-medium', plan.groupAllowMessagesDispatch ? (isDark ? 'text-green-400' : 'text-green-600') : isDark ? 'text-slate-400' : 'text-slate-500'].join(' ')}>
                                 {plan.groupAllowMessagesDispatch ? '已启用' : '未启用'}
                               </div>
                             </div>
@@ -1241,7 +1241,7 @@ function SubscriptionsContent() {
                       {selectedGroup.platform?.toLowerCase() === 'openai' && (
                         <div>
                           <span className={isDark ? 'text-slate-500' : 'text-slate-400'}>/v1/messages 调度</span>
-                          <div className={['mt-0.5 font-medium', selectedGroup.allow_messages_dispatch ? 'text-green-600 dark:text-green-400' : isDark ? 'text-slate-400' : 'text-slate-500'].join(' ')}>
+                          <div className={['mt-0.5 font-medium', selectedGroup.allow_messages_dispatch ? (isDark ? 'text-green-400' : 'text-green-600') : isDark ? 'text-slate-400' : 'text-slate-500'].join(' ')}>
                             {selectedGroup.allow_messages_dispatch ? '已启用' : '未启用'}
                           </div>
                         </div>
@@ -1431,7 +1431,7 @@ function SubscriptionsPageFallback() {
 
   return (
     <div className="flex min-h-screen items-center justify-center">
-      <div className="text-gray-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
+      <div className="text-slate-500">{locale === 'en' ? 'Loading...' : '加载中...'}</div>
     </div>
   );
 }