Aquí uno para jugar con el justify-content, tomado de w3schools
los valores:
flex-start flex-end center space-between space-around space-evenly
<!DOCTYPE html>
<html>
<head>
<style>
#main {
width: 400px;
height: 100px;
border: 1px solid #c3c3c3;
display: flex;
justify-content: center;
}
#main div {
width: 70px;
height: 70px;
}
</style>
</head>
<body>
<h1>The justify-content Property</h1>
<p>The "justify-content: center;" aligns the flex items at the center of the container:</p>
<div id="main">
<div style="background-color:coral;">1</div>
<div style="background-color:lightblue;">2</div>
<div style="background-color:pink;">3</div>
</div>
<p><b>Note:</b> Internet Explorer 10 and earlier versions do not support the justify-content property.</p>
</body>
</html>
