fix(menu): change style

src/packages/__VUE/menuitem/index.scss

@@ -45,13 +45,13 @@
 
 .nut-menu-item-placeholder-element {
   position: fixed;
-  top: -$menu-bar-line-height;
+  top: $menu-bar-line-height;
   left: 0;
   right: 0;
   z-index: $menu-bar-opened-z-index;
   background-color: transparent;
 
   &.up {
-    bottom: -$menu-bar-line-height;
+    bottom: $menu-bar-line-height;
   }
 }

src/packages/__VUE/menuitem/index.taro.vue

@@ -3,7 +3,7 @@
     <div
       v-show="state.isShowPlaceholderElement"
       @click="handleClickOutside"
-      class="placeholder-element"
+      class="nut-menu-item-placeholder-element"
       :class="{ up: parent.props.direction === 'up' }"
       :style="placeholderElementStyle"
     >