/ref-filled-green-100px-square.xht">
<meta name="assert" content="The 'align-self' property set 'center' centered the flex items in the cross axis within the line">
<style>
  #test {
    background-color: red;
    display: flex;
    height: 100px;
    width: 100px;
  }
  #test div {
    align-self: center;
    background-color: green;
    height: 50px;
    width: 25px;
  }
  #top {
    background-color: green;
    margin-top: -100px;
    height: 25px;
    width: 100px;
  }
  #bottom {
    background-color: 