vertical-align:middle 实现垂直居中第二个盒子添加vertical-align:middle 思路

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .wrapper {
            width: 500px;
            height: 500px;
            background-color: pink;
            text-align: center;
            margin: 0 auto;
        }

        .box {
            width: 100px;
            height: 100px;
            background-color: deepskyblue;
            display: inline-block;
            vertical-align: middle;
            /* margin: 0 auto; */
        }
        .box1 {
            width: 100px;
            height: 100px;
            background-color: orange;
            display: inline-block;
            /* vertical-align:middle */
        }
        
    </style>
</head>

<body>

    <div class="wrapper">
        <div class="box"></div>
        <div class="box1"></div>
    </div>

</body>

</html>

第二个盒子添加vertical-align:middle

思路：

让class="box"的div在class="wrapper"的div里面垂直居中，我可以在class="wrapper"的div里面加一个div空标签，把它的高度设为100%，宽度设置为0，再给它一个vertical-align:middle样式，同样的给class="box"的div一个vertical-align:middle样式，那么box就可以在div里面垂直居中了。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CSS垂直居中</title>
    <style>
        .wrapper{
            width: 500px;
            height: 500px;
            background-color: pink;

            text-align: center;
        }

        .box{
            width: 100px;
            height: 100px;
            background-color: deepskyblue;

            display: inline-block;
            vertical-align: middle;
            margin: 0 auto;
        }

        .help{
        width: 0;
        height: 100%;
        display: inline-block;
        vertical-align: middle;
        }
    </style>
</head>
<body>
<div class="wrapper">
    <div class="box"></div>
    <div class="help"></div>
</div>
</body>
</html>