CSS之DIV布局样式class

<style type="text/css">

.header{
color:blue;
width:100%;
height:200px;
background-color:green;
border-color:red 5px solid;
}
.left{
color:white;
background-color:rgba(0,0,0,1.00);
width:49%;
height:200px;
<span style="color:#CC0000;"> float:left;</span>
}

.right{
color:orange;
background-color:red;
width:49%;
height:200px;
<span style="color:#CC0000;">position:relative;
float:right;</span>
}
</style>