style(ui): 播放页间距等宽 + 控制行上移 25 + 进度条重写

- 标题/歌手/专辑的间距统一为 10，视感更整齐
- 底部留白 70 -> 45（控制行上移 25）
- 进度条改用 LayoutBuilder + Positioned 绝对宽度，
  背景/缓冲/已播三层顺序明确，不再出现两端亮块

lib/pages/player_page.dart

@@ -308,7 +308,7 @@ class _PlayerPageState extends BaseState<PlayerPage> {
   Widget _buildMainPage(AudioService service, Song song, bool isPlaying) {
     return Padding(
       // 顶部留 16：与 AppBar/指示器拉开距离，避免封面贴着顶部
-      padding: const EdgeInsets.fromLTRB(24, 16, 24, 0),
+      padding: const EdgeInsets.fromLTRB(24, 24, 24, 0),
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
@@ -366,17 +366,17 @@ class _PlayerPageState extends BaseState<PlayerPage> {
               ),
             ],
           ),
-          const SizedBox(height: 2),
+          const SizedBox(height: 10),
           Text(
             song.artist,
-            style: TextStyle(fontSize: 14, color: Colors.grey[400]),
+            style: TextStyle(fontSize: 16, color: Colors.grey[300]),
             maxLines: 1,
             overflow: TextOverflow.ellipsis,
           ),
 
           // ---- 信息区（专辑 / 目录）----
           if (_album.isNotEmpty || _folder.isNotEmpty) ...[
-            const SizedBox(height: 14),
+            const SizedBox(height: 10),
             if (_album.isNotEmpty)
               Text(
                 _album,
@@ -409,7 +409,8 @@ class _PlayerPageState extends BaseState<PlayerPage> {
 
           // ---- 控制 ----
           _buildControlButtons(service, song, isPlaying),
-          const SizedBox(height: 20),
+          // 底部多留 50px：控制行整体上移
+          const SizedBox(height: 45),
         ],
       ),
     );
@@ -548,20 +549,31 @@ class _PlayerPageState extends BaseState<PlayerPage> {
                 Expanded(
                   child: SizedBox(
                     height: 24,
-                    child: Stack(
+                    child: LayoutBuilder(
+                      builder: (context, constraints) {
+                        final width = constraints.maxWidth;
+                        return Stack(
                           alignment: Alignment.centerLeft,
                           children: [
-                        Container(
+                            // 背景轨道
+                            Positioned(
+                              left: 0,
+                              right: 0,
+                              top: 10.5,
+                              child: Container(
                                 height: 3,
                                 decoration: BoxDecoration(
                                   color: Colors.grey[800],
                                   borderRadius: BorderRadius.circular(2),
                                 ),
                               ),
-                        FractionallySizedBox(
+                            ),
-                          alignment: Alignment.centerLeft,
+                            // 已缓冲
-                          widthFactor: bufferProgress.clamp(0.0, 1.0),
+                            Positioned(
+                              left: 0,
+                              top: 10.5,
                               child: Container(
+                                width: width * bufferProgress.clamp(0.0, 1.0),
                                 height: 3,
                                 decoration: BoxDecoration(
                                   color: const Color(0xFF4A7A7A),
@@ -569,10 +581,13 @@ class _PlayerPageState extends BaseState<PlayerPage> {
                                 ),
                               ),
                             ),
-                        FractionallySizedBox(
+                            // 已播放
-                          alignment: Alignment.centerLeft,
+                            Positioned(
-                          widthFactor: displayProgress.clamp(0.0, 1.0),
+                              left: 0,
+                              top: 10.5,
                               child: Container(
+                                width:
+                                    width * displayProgress.clamp(0.0, 1.0),
                                 height: 3,
                                 decoration: BoxDecoration(
                                   color: const Color(0xFFB8D4D0),
@@ -612,6 +627,8 @@ class _PlayerPageState extends BaseState<PlayerPage> {
                               ),
                             ),
                           ],
+                        );
+                      },
                     ),
                   ),
                 ),