<div class="select_btn">
     <el-select v-model="subItemVal"  size="small" style="width: 120px" :popper-append-to-body="false">
         <el-option v-for="(item,i) in subItemData" :key="i" :label="item.name" :value="item.number" />
     </el-select>
 </div>

.select_btn{
  position: absolute;
   top: 5px;
   right: 60px;
   //下拉框
   .el-select-dropdown{
       border: none;
       background-color: rgba(1, 28, 82, 0.8);
   }
   //输入框
   .el-input__inner{
       color:#eee;
       border-color: #00fff6;
       background-color: rgba(1, 28, 82, 0.8);
   }
   //聚焦时的样式
   .el-select .el-input.is-focus .el-input__inner{
       border-color: #0B61AA;
       background-color: rgba(1, 28, 82, 0.8);
       color:#00D3E9;
   }
   //下拉框选中
   .el-select-dropdown__item{
       color: #eee;
   }
   //鼠标经过下拉框
   .el-select-dropdown__item.hover, 
   .el-select-dropdown__item:hover{
       color:#00D3E9;
       background-color: #0F3360;
   }
}