fix: 修复输入框和按钮在暗色模式下的样式问题

- 为 :root 和 .dark 添加 color-scheme，使浏览器表单控件默认样式适配暗色模式
- 将 bg-primary 搭配 text-white 的按钮改为 text-primary-foreground
- 替换残留的 hover:bg-blue-700、text-blue-500、bg-gray-200 等硬编码颜色
- 同步更新 TextInputArea 单元测试

pages/Base64Converter/FileMode.tsx

@@ -195,7 +195,7 @@ export default function FileMode() {
               }}
             />
             {isLoading ? (
-              <div className="w-10 h-10 border-4 border-primary/30 border-t-blue-600 rounded-full animate-spin" />
+              <div className="w-10 h-10 border-4 border-primary/30 border-t-primary rounded-full animate-spin" />
             ) : info ? (
               <div className="flex flex-col items-center gap-1">
                 <Upload className="w-10 h-10 text-primary" />

pages/Base64Converter/ImageMode.tsx

@@ -202,7 +202,7 @@ export default function ImageMode() {
               }}
             />
             {isLoading ? (
-              <div className="w-10 h-10 border-4 border-primary/30 border-t-blue-600 rounded-full animate-spin" />
+              <div className="w-10 h-10 border-4 border-primary/30 border-t-primary rounded-full animate-spin" />
             ) : info ? (
               <div className="flex flex-col items-center gap-1">
                 {result && (

pages/JsonTools/JsonFormatSection.tsx

@@ -90,7 +90,7 @@ export default function JsonFormatSection() {
               type="checkbox"
               checked={sortKeys}
               onChange={(e) => setSortKeys(e.target.checked)}
-              className="h-4 w-4 rounded border-input text-blue-500 focus:ring-primary"
+              className="h-4 w-4 rounded border-input text-primary focus:ring-primary"
             />
             <span className="text-xs font-bold">{t('jsonFormat:sortKeys')}</span>
           </label>

pages/StorageCleaner/AutoRefreshToggle.tsx

@@ -19,7 +19,7 @@ export default function AutoRefreshToggle({ autoRefresh, onChange }: AutoRefresh
           onChange={(e) => onChange(e.target.checked)}
           className="sr-only peer"
         />
-        <div className="w-9 h-5 bg-gray-200 peer-focus:outline-none peer-focus:ring-2 peer-focus:ring-amber-300 rounded-full peer peer-checked:after:translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-background after:border-input after:border after:rounded-full after:h-4 after:w-4 after:transition-all peer-checked:bg-amber-500" />
+        <div className="w-9 h-5 bg-muted peer-focus:outline-none peer-focus:ring-2 peer-focus:ring-amber-300 rounded-full peer peer-checked:after:translate-x-full peer-checked:after:border-background after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-background after:border-input after:border after:rounded-full after:h-4 after:w-4 after:transition-all peer-checked:bg-amber-500" />
       </label>
     </div>
   );

pages/Timestamp/LiveClock.tsx

@@ -47,7 +47,7 @@ const LiveClock = React.memo(({ unit, onUseNow }: LiveClockProps) => {
       <button
         onClick={handleUseNow}
         title={t('timestamp:useNowTooltip')}
-        className="p-1.5 rounded-md bg-background text-primary shadow-sm hover:bg-blue-700 hover:text-white transition-colors"
+        className="p-1.5 rounded-md bg-background text-primary shadow-sm hover:bg-primary hover:text-primary-foreground transition-colors"
       >
         <Clock className="w-4 h-4" />
       </button>

pages/Timestamp/index.tsx

@@ -98,7 +98,7 @@ export default function Index() {
             {/* 立即转换 */}
             <button
               onClick={convert}
-              className="block mx-auto mt-4 mb-1 max-w-[240px] w-full py-2.5 text-sm font-semibold rounded-lg bg-primary text-white hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-primary focus:ring-offset-2 transition-all"
+              className="block mx-auto mt-4 mb-1 max-w-[240px] w-full py-2.5 text-sm font-semibold rounded-lg bg-primary text-primary-foreground hover:bg-primary/90 focus:outline-none focus:ring-2 focus:ring-primary focus:ring-offset-2 transition-all"
             >
               {t('timestamp:convertButton')}
             </button>