2-6两个问题

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>14.4css</title>
    <style type="text/css">
        *{margin: 0;
          padding: 0;
 
        }
        .header{
            width: 100%;
            height: 100px;
            background:black url(http://img1.sycdn.imooc.com/climg//58c0d2d900016ce303000100.png) no-repeat;
            left: 0;
            right:0;
            top: 0;
            bottom: 0;
            margin:0 auto;
            position: fixed;
 
        }
        .ul1{
            width: 60%;
            height: 60px;
            color: white;
            list-style: none;
            margin-left: 700px;
            margin-top: 35px
        }
        .li1{
            width:7%;
            height: 10px;
            display: inline-block;
            margin-left: 100px;
            margin-top: 10px
        }
        .one{margin-left: 100px;}
        .footer{
            width: 100%;
            height: 100px;
            background-color:black;
            position: fixed;
            bottom: 0px;
        }
        .ul2{
            width: 100%;
            height: 60px;
            color: white;
            list-style: none;
            margin-left: 10%;
            margin-right:10%;
        }
        .li2{
            width: 10%;
            height: 10px;
            display: inline-block;
            margin-left: 3%;
            margin-top:30px;
        }
        img{
            display: block;
        }
    </style>
</head>
<body>
    <div class="header">
        <ul class="ul1">
            <li class="li1">课程</li>
            <li class="li1">职业路径</li>
            <li class="li1" class="one" >实战</li>
            <li class="li1">猿问</li>
            <li class="li1">手记</li>
        </ul>
    </div>
    <div>
        <img src="http://img1.sycdn.imooc.com/climg//58c0eda50001e12416000480.jpg" width="100%" />
    </div>
    <div>
        <img src="http://img1.sycdn.imooc.com/climg//58c0edb80001c9f216000480.jpg" width="100%">
    </div>
    <div>
        <img src="http://img1.sycdn.imooc.com/climg//58c0edc9000100d516000480.jpg" width="100%">
    </div>
    <div class="footer">
        <ul class="ul2">
            <li class="li2">网站首页</li>
            <li class="li2">企业合作</li>
            <li class="li2">人才招聘</li>
            <li class="li2">联系我们</li>
            <li class="li2">常见问题</li>
            <li class="li2">友情链接</li>
    </div>
</body>
</html>