gulp4.js

import React from 'react';
import classnames from 'classnames';
import {
  container, navbar, navbarLight, bgFaded, navbarToggler, hiddenSmUp, collapse, navbarToggleableXs,
  navbarBrand, nav, navbarNav, navItem, active, navLink, srOnly, formInline, pullXsRight, btn,
  btnSuccessOutline, formControl, jumbotron, btnLg, btnPrimary,
} from '../../styles/bootstrap.m.css';

export default () => (
  <div className={container}>
    <nav className={classnames(navbar, navbarLight, bgFaded)}>
      <button className={classnames(navbarToggler, hiddenSmUp)} type="button" data-toggle="collapse" data-target="#navbar-header" aria-controls="navbar-header">
        &#9776;
      </button>
      <div className={classnames(collapse, navbarToggleableXs)}>
        <a className={navbarBrand} href="#">Navbar</a>
        <ul className={classnames(nav, navbarNav)}>
          <li className={classnames(navItem, active)}>
    ...
  </div>
);