CSS（０）CSS的引入方式

<!--在body内写入-->
<div></div>
        <div style = "width:100px;height:100px;background-color:#f40"> 

<!--代码在head内，作用在body内的div-->
<style type="text/css">
    div{
        width:100px;
        height:100px;
        background-color:blue
            }
</style>            

<link rel="stylesheet" type="text/css" href="css/one.css"/>

div{
        width:100px;
        height:100px;
        background-color:#008000
    }