微信基础库是:3.3.1

请问怎么才能自定义page-container的圆角呢?api自带的round圆角太大了,想自定义一个但是没有api

<page-container show="{{showpopup}}" >
      <view>
        <block>
          <view class="top_title">
            <image class="top_title_image" src="../../images/index/demo.jpg" mode="" />
            <view>添加商家客服二维码,进行申诉</view>
          </view>
          <view class="qc_weixin">
            <image class="qc_weixin_img" show-menu-by-longpress="{{true}}"   src="../../images/index/demo.jpg" alt="" />
            <view>长按识别二维码</view>
          </view>
        </block>
        <view class="phone_call">
            <view class="phone_call_img">
            <image   class="top_title_image" src="../../images/index/demo.jpg" mode=""/>
            <view>联系电话:  15053525656</view>
            </view>
            <view class="btn_call" bindtap="onContactService">呼叫</view>
         </view>
         <view class="cancel" bindtap='btnpopup_cancel'>取消</view>
      </view>
    </page-container>