fix: reserve bottom space for points tip

uniapp/src/packages/pages/points_center/points_center.vue

@@ -203,6 +203,7 @@ $line: #e8ebef;
 
     &__safe-area {
         height: 28rpx;
+        flex-shrink: 0;
     }
 }
 
@@ -381,6 +382,7 @@ $line: #e8ebef;
 .detail-card {
     flex: 1;
     min-height: 0;
+    height: 0;
     width: calc(100% - 56rpx);
     margin: 0 28rpx;
     padding: 0 20rpx;
@@ -470,11 +472,8 @@ $line: #e8ebef;
 }
 
 .points-tip {
-    position: fixed;
-    left: 28rpx;
-    right: 28rpx;
-    bottom: calc(120rpx + env(safe-area-inset-bottom));
-    z-index: 19;
+    margin: 20rpx 28rpx 0;
+    flex-shrink: 0;
     min-height: 60rpx;
     padding: 0 20rpx;
     display: flex;