<!DOCTYPE html>
<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
-->
<html>
<head>
  <title>
    CSS Reference
  </title>
  <style>
    div {
      border: 1px solid black;
      width: 50px;
      height: 20px;
      justify-content: center;
    }
  </style>
</head>
<body>
  <div style="display: flex;">a</div>
  <div style="display: flex;">b</div>
  <div style="display: flex;">c</div>
  <br>
  <div style="display: inline-flex;">d</div>
  <div style="display: inline-flex;">e</div>
  <div style="display: inline-flex;">f</div>
</body>
</html>