fix: 優化場景卡片滑動漸變效果

- 修復滑動區域右側漸變遮罩的色彩落差問題
- 使用多層次透明度漸變 (0.95→0.8→0.4→0)
- 增加漸變寬度從 60px 到 80px
- 提升視覺過渡的平滑度和自然感
- 符合 Apple 風格的精緻設計標準

🎨 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: yulin0629

style.css

@@ -538,8 +538,13 @@ body {
     top: 20px;
     right: 0;
     bottom: 20px;
-    width: 60px;
-    background: linear-gradient(to left, #fbfbfd 0%, rgba(251,251,253,0) 100%);
+    width: 80px;
+    background: linear-gradient(to left, 
+        rgba(251,251,253,0.95) 0%, 
+        rgba(251,251,253,0.8) 20%,
+        rgba(251,251,253,0.4) 60%,
+        rgba(251,251,253,0) 100%
+    );
     pointer-events: none;
     z-index: 1;
     opacity: 1;
@@ -552,8 +557,13 @@ body {
     top: 20px;
     left: 0;
     bottom: 20px;
-    width: 60px;
-    background: linear-gradient(to right, #fbfbfd 0%, rgba(251,251,253,0) 100%);
+    width: 80px;
+    background: linear-gradient(to right, 
+        rgba(251,251,253,0.95) 0%, 
+        rgba(251,251,253,0.8) 20%,
+        rgba(251,251,253,0.4) 60%,
+        rgba(251,251,253,0) 100%
+    );
     pointer-events: none;
     z-index: 1;
     opacity: 0;