fix: 图集详情下载区域增加渐变色

+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" fill="none" version="1.1" width="24" height="24" viewBox="0 0 24 24"><g transform="matrix(0,-1,1,0,-24,24)"><g><path d="M6.48671839,36.090092528686526C6.486514311,36.03864252868652,6.506040025,35.98713252868652,6.545295725,35.947872528686524L12.551938125,29.941231828686522C12.630038124999999,29.863126928686523,12.756678125,29.863126928686523,12.834778125,29.941231828686522L13.966148125,31.072602528686524C14.044258124999999,31.150702528686523,14.044258124999999,31.277342528686525,13.966148125,31.355442528686524L9.231508125,36.090092528686526L13.966148125,40.82478252868653C14.044258124999999,40.902882528686526,14.044258124999999,41.02948252868652,13.966148125,41.10758252868652L12.834778125,42.23898252868652C12.756678125,42.31708252868653,12.630038124999999,42.31708252868653,12.551938125,42.23898252868652L6.545295725,36.23231252868652C6.506040025,36.193062528686525,6.486514311,36.14154252868652,6.48671839,36.090092528686526Z" fill-rule="evenodd" fill="#FFFFFF" fill-opacity="1"/></g><g><rect x="9" y="35" width="12" height="2" rx="0.20000000298023224" fill="#FFFFFF" fill-opacity="1"/></g><g transform="matrix(0,-1,-1,0,50,50)"><g><path d="M5.144721,46.71056C5.0782313,46.84354,5.17493,47,5.323607,47L22.8,47C22.9105,47,23,46.91046,23,46.8L23,45.2C23,45.0895431,22.9105,45,22.8,45L6.12361,45C6.04785,45,5.9786,45.0428005,5.944721,45.110557L5.144721,46.71056Z" fill="#FFFFFF" fill-opacity="1"/></g></g></g></svg>
\ No newline at end of file

@@ -521,11 +521,16 @@ export struct MultiPictureDetailPageComponent {
               }))
       }
     }
-    .margin({
-      top: 14,
+    .padding({
+      top: 16,
       left: 20,
-      bottom: 14,
-      right: 0
+      bottom: 16,
+      right: 16
+    })
+    .linearGradient({
+      direction: GradientDirection.Bottom, // 渐变方向
+      colors: [['rgba(18, 18, 18, 0)', 0],
+        ['rgba(18, 18, 18, 0.8)', 1.0]] // 数组末尾元素占比小于1时满足重复着色效果
     })
     .transition(TransitionEffect.OPACITY.animation({ duration: this.duration, curve: Curve.Ease }).combine(
       TransitionEffect.translate({ x: 0, y: `${this.bottomSafeHeight}px` })