代码示例:(标识:css3_flexbox_margin_1)
<!DOCTYPE html>
<html>
<head>
<style> 
.flex-container {
  display: -webkit-flex;
  display: flex;
  width: 400px;
  height: 250px;
  background-color: lightgrey;
}

.flex-item {
  background-color: cornflowerblue;
  width: 75px;
  height: 75px;
  margin: 10px;
}

.flex-item:first-child {
  margin-right: auto;
}
</style>
</head>
<body>

<div class="flex-container">
  <div class="flex-item">flex item 1</div>
  <div class="flex-item">flex item 2</div>
  <div class="flex-item">flex item 3</div>  
</div>

</body>
</html>
运行结果: