html, body {
  margin: 0;
  padding: 50px;
  font-family: Arial, Helvetica, sans-serif;
  text-align: center;
}

/** 
  Our buttons '#open-modal, #close-modal' 

  1) For the background colour use 'royalblue'
  2) Be aware of the colour, padding & font size
  3) Make sure the cursor has a pointer so that it demonstrates to the user the button is clickable
**/