我刚刚了解到，只有当有多行时，‘Align-Content’属性才起作用.因为这个属性是关于项目行之间的. 因此，如果只有一行，则此属性不能有影响.
* {
box-sizing: border-box;
font-size: 1.5rem;
}
html {
background: #b3b3b3;
padding: 5px;
}
body {
background: #b3b3b3;
padding: 5px;
margin: 0;
}
.flex-container {
background: white;
padding: 10px;
height: 1300px;
border: 5px solid black;
display: flex;
flex-flow: wrap row;
justify-content: center;
align-items: center;
align-content:flex-start
}
.item-1 {
background: #ff7300;
color: white;
padding: 10px;
border: 5px solid black;
margin: 10px;
}
.item-2 {
background: #ff9640;
color: white;
padding: 10px;
border: 5px solid black;
margin: 10px;
width: 250px;
font-size: 1.8rem;
}
.item-3 {
background: #ff9640;
color: white;
padding: 10px;
border: 5px solid black;
margin: 10px;
height: 250px;
}
.item-4 {
background: #f5c096;
color: white;
padding: 10px;
border: 5px solid black;
margin: 10px;
width: 300px;
height: 300px;
}
.item-5 {
background: #d3c0b1;
color: white;
padding: 10px;
border: 5px solid black;
margin: 10px;
width: 350px;
}
.item-6 {
background: #d3c0b1;
color: white;
padding: 10px;
border: 5px solid black;
margin: 10px;
width: 350px;
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<link rel="stylesheet" href="main.css">
<title>Flexbox</title>
</head>
<body>
<div class="flex-container">
<div class="item-1">div</div>
<div class="item-2">w=250px</div>
<div class="item-3">h=250px</div>
<div class="item-4">w/h=300px</div>
<div class="item-5">w=350px</div>
<div class="item-6">w=350px</div>
</div>
</body>
</html>
但在这种情况下，我申请了
display: flex;
flex-flow: wrap row;
justify-content: center;
align-items: center;
align-content:flex-start
根据我所了解的，Align-Content应该不起作用，因为只有一行.因此，这些物品应该放在"弹性容器"的中心.
but it's placed on the top like below which it should not be
你能解释一下这件事吗？