<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.box{
width:400px;
height: 400px;
background: yellow;
position: absolute;
}
.center-item{
background: red;
width: 50px;
height: 50px;
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%,-50%);
;
}
.box1{
left: 420px;
width:400px;
height: 400px;
background: green;
position: relative;
}
.center-item1{
background: blueviolet;
width: 50px;
height: 50px;
position: absolute;
left: 0;
top: 0;
right: 0;
bottom: 0;
margin: auto;
}
.box2{
top: 8px;
left: 840px;
width:400px;
height: 400px;
background: cornflowerblue;
text-align: center;
position: absolute;
}
.box2 i{
display: inline-block;
vertical-align: middle;
height: 100%;
}
.center-item2{
background: purple;
width: 50px;
height: 50px;
display: inline-block;
vertical-align: middle;
}
.box3{
left: 0;
top: 20px;
width:400px;
height: 400px;
background:indianred;
position: relative;
display: flex;
align-items: center;/*垂直居中*/
}
.center-item3{
background: greenyellow;
width: 50px;
height: 50px;
margin: 0 auto;
}
</style>
</head>
<body>
<div class="box">
<div class="center-item">
</div>
</div>
<div class="box1">
<div class="center-item1">
</div>
</div>
<div class="box2">
<i></i>
<div class="center-item2">
</div>
</div>
<div class="box3">
<div class="center-item3">
</div>
</div>
</body>
</html>
