ALIGN-SELF

Run
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=">
  <style>
    .flex-container {
      display: flex;
      height: 10em;
      border: 4px solid #4c4c4c;
    }
    
    .flex-item {
      padding: 2em;
      background: #a37eba;
      color: #fff;
      margin: 0.25em;
    }
    
    .stretch {
      align-self: stretch;
    }
    .flex-start {
      align-self: flex-start;
    }
    .flex-end {
      align-self: flex-end;
    }
    .center {
      align-self: center;
    }
    .baseline {
      align-self: baseline;
    }
    
    body {
      font-family: sans-serif;
      font-size: 20px;
    }

  </style>
  <title>Align-Self</title>
</head>

<body>
  <div class="flex-container">
    <div class="flex-item stretch">stretch</div>
    <div class="flex-item flex-start">flex-start</div>
    <div class="flex-item flex-end">flex-end</div>
    <div class="flex-item center">center</div>
    <div class="flex-item baseline">baseline</div>
  </div>
</body>

</html>