FLEX-GROW
Run 
<!doctype html>
	<head>
		<style>
			/* CSS comes here */
        .flex-container {
          display: flex;
        }
        .flex-item {
          height: 150px;
          width: 150px;
          margin: 5px;
          font-size: 30px;
          padding: 10px;
        }
        .blue {
          background-color: blue;
          color: white;
        }
        /* The flex-grow Property */
        .item-1 {
          flex-grow: 2;
        }
        
        .item-2 {
          flex-grow: 1;
        }
        
        /* Google Fonts Setup */
        body {
          font-family: "Roboto", sans-serif;
        }	
		</style>
		<title>Flex Grow</title>
	</head>
	<body>
      <div class="flex-container">
        <div class="flex-item item-1 blue">1</div>
        <div class="flex-item item-2 blue">2</div>
        <div class="flex-item item-3 blue">3</div>
        <div class="flex-item item-4 blue">4</div>
      </div>
    </body>
</html>