修改大标题

src/views/Home.vue

 <template>
   <div class="home" style="position: relative" id="home">
     <!-- nav -->
-    <img class="nav" src="../assets/img/gisdemo/top.png">
+    <div class="nav"></div>
     <!-- 地图 -->
     <div id="map"></div>
     
                   <el-submenu :index="index+'-1'">
                     <template slot="title">反演结果</template>
                     <el-menu-item v-for="($item, $index) in item.item"
-                    :key="$index" :index="index + '-1' + $index" @click="selectParams($item.value, $index)">{{$item.name}}: {{ $item.type.toUpperCase() }}</el-menu-item>
+                    :key="$index" :index="index + '-1' + $index" @click="selectParams($item.value, index, $index)">{{$item.name}}: {{ $item.type.toUpperCase() }}</el-menu-item>
                   </el-submenu>
                 </el-menu-item-group>
                 <el-menu-item-group>
     },
 
     // 选择反演参数
-    selectParams(id, $index) {
+    selectParams(id, index, $index) {
       // 1.显示四参数的图层并展示对应的图层
       console.log(this.checkedRiver);
       this.tileDong.setVisible(true);
 .nav {
   z-index: 99;
   width: 100%;
-  height: auto;
+  height: 50px;
+  background-image: url('../assets/img/gisdemo/top.png');
+  background-size: cover;
   position: absolute;
   top: 0px;
 }