// wxml
<view class="view_2">
    <van-tabs active="{{ active }}" bind:change="onChange" color="#144a9e">
      <van-tab title="xxx">
        <block wx:for="{{DocumentList2}}" wx:key="index" class="DucumentList" data-index="{{ index }}">
          <van-cell title="{{item.filename}}" label="{{item.modifyTime}}" bind:click="cellTo2" data-index="{{index}}">
            //...
          </van-cell>
        </block>
      </van-tab>
     </van-tabs>
    </van-tabs>
</view>

// wxss
.view_2 {
    width: 100%;
    border-top-left-radius: 50rpx;
    border-top-right-radius: 50rpx;
    background-color: white;
   
    /* background: #f0eeed; */
  }