<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Flexbox</title>
  </head>
<body>
   <div class="container">
    <div class="item" id="one">1</div>
    <div class="item" id="two">2</div>
    <div class="item" id="flex">3</div>
   </div>
  <br>
  <div class="container2">
    <div class="item" id="one">1</div>
    <div class="item" id="two">2</div>
    <div class="item" id="flex">3</div>
   </div>
  
  
  <br>
  <div class="container3">
    <div class="item" id="one">1</div>
    <div class="item" id="two">2</div>
    <div class="item" id="flex">3</div>
   </div>
  
  <br>
  <div class="container4">
  <div>1</div>
  <div>2</div>
  <div>3</div>  
</div>
  
   <br>
 <div class="container5">
  <div><h1>1</h1></div>
  <div><h6>2</h6></div>
  <div><h3>3</h3></div>  
  <div><small>4</small></div>  
</div>
  </body>
</html>
.container{
            display: flex;
            height: 100px;
            border: 1px solid #808080;
            align-items: flex-start;
           }

.container2{
            display: flex;
            height: 100px;
            border: 1px solid #808080;
            align-items: center;
            }

.container3{
            display: flex;
            height: 100px;
            border: 1px solid #808080;
            align-items: flex-end;
             
        }

.container4{
            display: flex;
            height: 200px;
            border: 1px solid #808080;
            align-items: stretch;
            background-color: #46B2E0;
        }

.container5{
            display: flex;
            height: 200px;
            border: 1px solid #808080;
            align-items: baseline;
            background-color: #46B2E0;
             
        }


.container4 > div {
  background-color: #f1f1f1;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}


.container5 > div {
  background-color: #f1f1f1;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}

.item {
            border: 1px solid #1d1d1d;
            background-color: #23C4ED;
             width: 50px;
             height: 50px;
             margin: 7px;
            }

External CSS

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External JavaScript

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