<style type="text/css">
			
    body{
        padding: 0px;
        margin:0px;
    }

    #header{
        width:100%;
        /*background-color: lightblue;*/
    }

    #navigator, #navigator1{
        width:100%;
        background-color:gold; 
        text-align: center;
        height:150px;
        font:bold 75px/150px 'Microsoft Yahei';
        /*opacity: 0.5;*/
    }
    /*用于当navigator脱离文档流时，navigator1来进行填充原来的空位*/
    #navigator1{
        /*由于刚开始，navigator(即菜单栏)没有脱离文档流，所以先不展示navigator1*/
        display:none;
    }

    .else{
        width:100%;
        height:200px;
        background-color: green;
    }

    .text{
        text-align: center;
        font:bold 25px/25px 'Microsoft Yahei';
    }


</style>