title: React bootstrap 4 modal window close button bad formatting
body: <p>I am trying make modal window in reactjs with bootstrap 4. When I use bootstrap 4 I have problem with css formatting with close button. When I use bootstrap 3 css are ok. 
  There is my <a href="https://codesandbox.io/s/7jyq2zxlj6" rel="nofollow noreferrer">code</a> . Thank you for advice.</p>