abstract：<!--CSS基础--><!DOCTYPE html><html><head> <meta charset="utf-8"> <title>CSS第三节课--边框</title> <link rel="shortcut icon" type="images/x
<!--CSS基础-->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>CSS第三节课--边框</title>
<link rel="shortcut icon" type="images/x-icon" href="images/logo.jpg">
<link rel="stylesheet" type="text/css" href="css/index.css">
<style type="text/css">
/**{padding:0px;margin: 0px;}浏览器自带边距清零*/
.box{width: 100px;height: 100px;border:1px /*solid double dashed */ dotted #ccc;border-radius: 10px;}
.main{width: 100px;height: 100px;border-top:1px solid red;background: #ccc;}
button{border: none;}
.shadow{width: 100px;height: 40px;box-shadow: 0px 6px 30px #ccc inset;border: 1px solid #ccc;text-align: center;line-height: 40px;}
.shadow:hover{box-shadow: 0px 6px 30px red inset;}
</style>
</head>
<body>
<!--<div class="box"></div>
<div class="main"></div>
<button>登录</button>-->
<div class="shadow" style="float: left;">HTML</div>
<div class="shadow" style="float: left;">CSS</div>
<div class="shadow" style="float: left;">JavaScript</div>
</body>
</html>