feat(Upload): add styles for drag interaction

Author: Reuse5653

style/mobile/components/upload/_index.less

@@ -14,12 +14,31 @@
     height: @upload-height;
     border-radius: @upload-radius;
     overflow: hidden;
+    transition: all @anim-duration-base ease-in-out;
 
     &--add {
       font-size: @upload-add-icon-font-size;
       background: @upload-background;
       color: @upload-add-color;
     }
+    
+    &--dragging {
+      opacity: 0.9;
+      transform: scale(1.05);
+      box-shadow: @shadow-2;
+    }
+
+    &--drag-over::before {
+      content: '';
+      position: absolute;
+      top: 0;
+      left: 0;
+      width: 100%;
+      height: 100%;
+      box-shadow: inset 0 0 0 1px @brand-color;
+      border-radius: @upload-radius;
+      z-index: 1;
+    }
   }
 
   &__add-icon {