<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
/*1.标签选择器: 会选择所有的div标签*/
div{
width: 100px;
height: 100px;
background-color: red;
border: 1px solid black;
}
/*2.类选择器：*/
.box{
width: 100px;
height: 100px;
background-color: green;
border: 1px solid black;
}
/*3.id选择器*/
width: 100px;
height: 100px;
background-color: blue;
border: 1px solid black;
}
</style>
</head>
<body>
<div>11111</div>
<div class="box">22222</div>
<div id="box02">22222</div>
</body>
</html>
