将justify-content属性与值flex-start一起使用，可以在开始时对齐flex-item。
您可以尝试运行以下代码来实现flex-start值
<!DOCTYPE html>
<html>
<head>
<style>
.mycontainer {
display: flex;
background-color: red;
justify-content: flex-start;
}
.mycontainer > div {
background-color: orange;
text-align: center;
line-height: 60px;
font-size: 30px;
width: 100px;
margin: 5px;
}
</style>
</head>
<body>
<h1>Result</h1>
<div class = "mycontainer">
<div>Rank1</div>
<div>Rank2</div>
<div>Rank3</div>
<div>Rank4</div>
</div>
</body>
</html>