feat(widgets): 优化 KodBoxCard 组件的样式和布局

- 增加卡片的阴影和圆角，提升视觉效果
- 调整卡片内各元素的样式和间距，增强可读性
- 优化 KodBox 最近操作部分的样式，增加紫色主题元素
- 改进错误提示和空状态的显示效果

lib/widgets/kodbox_card.dart

@@ -119,45 +119,84 @@ class _KodBoxCardState extends State<KodBoxCard> {
     final sourceID = isFileOperation ? _getSourceID(desc) : null;
 
     return Card(
-      margin: const EdgeInsets.symmetric(vertical: 4.0),
+      elevation: 2,
+      margin: const EdgeInsets.symmetric(vertical: 6.0),
+      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
       child: InkWell(
         onTap: sourceID != null ? () => _launchFileUrl(sourceID) : null,
+        splashColor: Colors.deepPurple.withAlpha(30),
         child: Padding(
-          padding: const EdgeInsets.all(12.0),
+          padding: const EdgeInsets.all(16.0),
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.start,
             children: [
               Row(
                 children: [
                   CircleAvatar(
-                    radius: 16,
+                    backgroundColor: Colors.deepPurple.shade200,
-                    child: Text(log['nickName']?[0].toUpperCase() ?? '?'),
+                    radius: 18,
+                    child: Text(
+                      log['nickName']?[0].toUpperCase() ?? '?',
+                      style: const TextStyle(color: Colors.white),
                     ),
-                  const SizedBox(width: 8),
+                  ),
+                  const SizedBox(width: 12),
+                  Expanded(
+                    child: Column(
+                      crossAxisAlignment: CrossAxisAlignment.start,
+                      children: [
                         Text(
                           log['nickName'] ?? log['name'] ?? '未知用户',
-                    style: const TextStyle(fontWeight: FontWeight.bold),
+                          style: const TextStyle(
+                            fontWeight: FontWeight.bold,
+                            fontSize: 16,
+                          ),
+                        ),
+                        if (log['title'] != null)
+                          Text(
+                            log['title']!,
+                            style: const TextStyle(
+                              fontSize: 14,
+                              color: Colors.grey,
+                            ),
+                          ),
+                      ],
+                    ),
                   ),
-                  const SizedBox(width: 8),
-                  Text(log['title'] ?? '未知操作'),
                 ],
               ),
               if (isFileOperation) ...[
-                const SizedBox(height: 8),
+                const SizedBox(height: 12),
-                Text(
+                Row(
+                  children: [
+                    const Icon(Icons.insert_drive_file,
+                        size: 18, color: Colors.deepPurple),
+                    const SizedBox(width: 8),
+                    Expanded(
+                      child: Text(
                         '文件路径: ${_getFilePath(desc)}',
                         style: TextStyle(
                           color: sourceID != null ? Colors.blue : Colors.black,
+                          fontSize: 14,
+                        ),
                       ),
                     ),
                   ],
+                ),
+              ],
               const SizedBox(height: 8),
+              Row(
+                children: [
+                  const Icon(Icons.access_time, size: 16, color: Colors.grey),
+                  const SizedBox(width: 6),
                   Text(
                     '时间: ${timeago.format(DateTime.fromMillisecondsSinceEpoch(int.parse(log['createTime']) * 1000), locale: 'zh_CN')}',
                     style: const TextStyle(fontSize: 12, color: Colors.grey),
                   ),
                 ],
               ),
+            ],
+          ),
         ),
       ),
     );
@@ -172,6 +211,9 @@ class _KodBoxCardState extends State<KodBoxCard> {
   @override
   Widget build(BuildContext context) {
     return Card(
+      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
+      elevation: 4,
+      margin: const EdgeInsets.all(16),
       child: Padding(
         padding: const EdgeInsets.all(16.0),
         child: Column(
@@ -182,36 +224,60 @@ class _KodBoxCardState extends State<KodBoxCard> {
               children: [
                 const Text(
                   'KodBox 最近操作',
-                  style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
+                  style: TextStyle(
+                    fontSize: 20,
+                    fontWeight: FontWeight.bold,
+                    color: Colors.deepPurple,
                   ),
-                IconButton(
+                ),
-                  icon: const Icon(Icons.refresh),
+                Container(
+                  decoration: BoxDecoration(
+                    color: Colors.deepPurple.shade100,
+                    borderRadius: BorderRadius.circular(20),
+                  ),
+                  padding: const EdgeInsets.all(8),
+                  child: IconButton(
+                    icon: const Icon(Icons.refresh, color: Colors.deepPurple),
                     onPressed: _isLoading ? null : _fetchLogs,
                   ),
+                ),
               ],
             ),
             if (_isLoading)
               const Center(
                 child: Padding(
-                  padding: EdgeInsets.all(16.0),
+                  padding: EdgeInsets.all(24.0),
-                  child: CircularProgressIndicator(),
+                  child: CircularProgressIndicator(color: Colors.deepPurple),
                 ),
               )
             else if (_error != null)
               Center(
                 child: Padding(
-                  padding: const EdgeInsets.all(16.0),
+                  padding: const EdgeInsets.all(24.0),
+                  child: Row(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    children: [
+                      const Icon(Icons.error_outline, color: Colors.red),
+                      const SizedBox(width: 8),
+                      Expanded(
                         child: Text(
                           _error!,
                           style: const TextStyle(color: Colors.red),
+                          textAlign: TextAlign.center,
+                        ),
+                      ),
+                    ],
                   ),
                 ),
               )
             else if (_logs.isEmpty)
               const Center(
                 child: Padding(
-                  padding: EdgeInsets.all(16.0),
+                  padding: EdgeInsets.all(24.0),
-                  child: Text('暂无操作记录'),
+                  child: Text(
+                    '暂无操作记录',
+                    style: TextStyle(fontSize: 16, color: Colors.grey),
+                  ),
                 ),
               )
             else