Realize the text in H5 to be centered horizontally and vertically, div centered horizontally
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#big{
width: 300px;
height: 300px;
background: green;
}
#small{
width: 100px;
height: 100px;
background: yellow;
/* 水平居中 */
/* margin: 0 auto; */
/* 不能竖直都居中 因为网页是无限拉长的*/
margin: auto auto;
/* 文字水平居中 */
text-align: center;
/* 文字竖直居中 */
line-height: 100px;
}
</style>
</head>
<body>
<div id="big">
<div id="small">Hello</div>
</div>
</body>
</html>
