title: How should I use css in reactJS?
body: <p>I am new to reactJS with ES6 and have read a lot about CSS and the problem they are trying to solve is the global <code>style.css</code> and instead use</p>
  
  <p>styles/index.js</p>
  
  <pre><code>var styles = {
    transparentBg: {
      background: 'transparent'
    }
  };
  </code></pre>
  
  <p>Many argue that you should go back and write CSS (I do not know what reacts name is for CSS, the code above) in each class instead of a separate file if you do not have hundreds of CSS classes. This feels weird. Is it true?</p>
  
  <p>Many CSS frameworks, as popular Bootstrap is still in "old" CSS. Does it matter? Know that the application still works but there must be some reason that react chosen to do it this way. Can I do something about it?</p>
  
  <p>What is the best practice when using CSS and CSS frameworks with ReactJS?</p>