text: import React, { Component } from 'react'
  import { Menu } from 'antd';
  const SubMenu = Menu.SubMenu;
  
  export default class Top extends Component {
    render() {
      return (
        <Menu theme="dark" mode="horizontal"
          defaultSelectedKeys={['2']} style={{lineHeight: '64px'}}>
          <Menu.Item key="1">导航一</Menu.Item>
          <Menu.Item key="2">导航二</Menu.Item>
          <Menu.Item key="3">导航三</Menu.Item>
        </Menu>
      );
    }
  };