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console

<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=, initial-scale=">
	<meta http-equiv="X-UA-Compatible" content="">
	<title></title>
</head>
<body>
	<div class="parent">
        <div class="son">111</div>
    </div>
</body>
</html>

.parent::after, .son{
    display:inline-block;
    vertical-align:middle;
}
.parent::after{
    content:'';
    height:100%;
}

.parent {
    width: 100px;
    height: 100px;
    border: 1px solid red;
}