CSS补充之页面布局

主站一：（下面是一个大致的模板）

<body>
    <div class="pg-header">
        <div style=" 980px;margin: 0 auto;">
                这里的内容会自动居中
        </div>
    </div>
    <div class="pg-content"></div>
    <div class="pg-footer"></div>
</body>

这样是把网站分为了上中下三部分，最上面是头部，中间是主要内容，下面是底部的信息。

后台管理布局

布局一，效果图如下：

当滑动右边滚动条的时候其他区域保持不变只有aaa占的部分会发生滚动

代码实现如下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            margin: 0;
        }
        .pg-header{
            height: 48px;
            background-color: #2459a2;
            color: white;
        }
        .left{
            float: left;
        }
        .right{
            float: right;
        }
        .pg-content .menu{
            position: fixed;
            top: 48px;
            left: 0;
            bottom: 0;
             200px;
            background-color: #dddddd;
        }
        .pg-content .content{
            position: fixed;
            top: 48px;
            bottom: 0;
            right: 0;
            left: 200px;
            background-color:green;
            overflow: auto;
        }
    </style>
</head>
<body>
    <div class="pg-header"></div>
    <div class="pg-content">
        <div class="menu left">a</div>
        <div class="content left">
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
            <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>

        </div>
    </div>
    <div class="pg-footer"></div>
</body>

布局二，效果图如下（这种是必须会的，后台布局经常用）

这种情况是当滑动滚轮的时候，左边菜单不会跟着走，即：

因为滑动，左边已经没有菜单，实现代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            margin: auto;
        }
        .pg-header{
            height: 48px;
            background-color: #2459a2;
            color: white;
        }
        .left{
            float: left;
        }
        .right{
            float: right;
        }
        .pg-content .menu{
            position: absolute;
            top: 48px;
            left:0;
            bottom: 0;
             200px;
            background-color: #dddddd;
        }
        .pg-content .content{
            position: absolute;
            top: 48px;
            right: 0;
            bottom: 0;
            left:200px;
        }
    </style>
</head>
<body>
    <div class="pg-header"></div>
    <div class="pg-content">
        <div class="menu left">a</div>
        <div class="content left">
            <div style="background: green;">
                <p style="margin: 0">aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>

            </div>

        </div>
    </div>
    <div class="pg-footer"></div>
</body>
</html>

还有当页面缩小到一定程度时，为了防止页面的内容显示发生变化，左右会出现滚动条，效果如下所示：

只需设置min-width 参数即可：

        .pg-content .content{
            position: absolute;
            top: 48px;
            right: 0;
            bottom: 0;
            left:200px;
            min- 980px;
        }

其实这里如果想要和布局一有相同的效果只需要更改一个地方就可以实现：（这种设置用的也是最多的）

        .pg-content .content{
            position: absolute;
            top: 48px;
            right: 0;
            bottom: 0;
            left:200px;
            min- 980px;
            overflow: auto;
        }

做一个简单的后台管理页面

首先需要记住一个地址：

http://fontawesome.io/

这个地址中存放了我们需要的各种图标，如下所示：

将文件下载下来

通过在头部导入：

做出的效果图如下所示：

当把鼠标放在头像的时候显示资料和注销信息，图片中的图标就是从下载的图标中直接引用的

实现代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="fontawesome-free-5.3.1-webcssfontawesome.min.css" />
    <style>
        body{
            margin: auto;
        }
        .pg-header{
            height: 48px;
            background-color: #2459a2;
            color: white;
            min- 500px;
            line-height: 48px;
        }
        .pg-header .icons{
            padding: 0 20px;
        }
        .pg-header .icons:hover{
            background-color: blue;
        }
        .pg-header .logo{
             200px;
            background-color: deepskyblue;
            text-align: center;

        }
        .pg-header .user{
             200px;
            background-color:deepskyblue ;
            text-align: center;
            height: 48px;
        }
        .pg-header .user:hover{
            background-color: blue;
        }
        .pg-header .user .b{
            z-index: 10;
            position: absolute;
            top: 48px;
            right: 0px;
            background-color: white;
            color: black;
             200px;
            display: none;
        }
        .pg-header .user:hover .b{
            display: block;
        }
        .pg-header .user .b a{
            display: block;
        }
        .left{
            float: left;
        }
        .right{
            float: right;
        }
        .pg-content .menu{
            position: absolute;
            top: 48px;
            left:0;
            bottom: 0;
             200px;
            background-color: #dddddd;
        }
        .pg-content .content{
            position: absolute;
            top: 48px;
            right: 0;
            bottom: 0;
            left:200px;
            overflow: auto;
            min- 500px;
            z-index: 9;
        }
    </style>
</head>
<body>
    <div class="pg-header">
        <div class="logo left">
            Tbb
        </div>

        <div class="user right">
            <a>
                <img src="logo.png" style="height: 40px; 40px;margin-top: 4px;border-radius: 50%">
            </a>
            <div class="b">
                <a>我的资料</a>
                <a>注销</a>
            </div>
        </div>
        <div class="icons right">
            <!--<i class="fa fa-bell-o" aria-hidden="true"></i>-->
            <i class="far fa-envelope"></i>
        </div>
        <div class="icons right">
            <!--<i class="fa fa-envelope-o" aria-hidden="true"></i>-->
            <i class="far fa-bell" style="font-size: 48px;"></i>
        </div>
    </div>
    <div class="pg-content">
        <div class="menu left">a</div>
        <div class="content left">
            <div style="background: green;">
                <p style="margin: 0">aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>
                <p>aaa</p><p>aaa</p><p>aaa</p><p>aaa</p>

            </div>

        </div>
    </div>
    <div class="pg-footer"></div>
</body>
</html>