course_freecodecamp/flexbox10.html

<!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>Document</title>
    <style>
        #box-container {
          display: flex;
          height: 500px;
        }
      
        #box-1 {
          background-color: dodgerblue;
          height: 200px;
          flex-basis: 10em;
        }
      
        #box-2 {
          background-color: orangered;
          height: 200px;
          flex-basis: 20em;
        }
      </style>
</head>
<body>
    <div id="box-container">
        <div id="box-1"></div>
        <div id="box-2"></div>
    </div>
</body>
</html>