adding_class_with_css_modules.js

import style from './style'
import React from 'react'

const Btn = React.createClass({
  render () {
    return (
      <button className={style.Btn}>
        Submit
      <button>
    )
  }
})

style.css

.Btn {
  padding: .8em 1.5em;
  color: white;
  background-color: #EC87C0;
  border: none;
}