2）前端的css排版布局-web开发-互联网-天达云

2）前端的css排版布局
更新：HHH 时间：2023-1-7

回顾重点：

伪元素选择器：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        p:first-letter{
            color: red;
        }
    </style>
</head>
<body>
<p>李晓峰</p>
</body>
</html>

在名字前面加字段博客作者：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        p:first-letter{
            color: red;
        }
        p:before{
            content: '博客作者'
        }
    </style>
</head>
<body>
<p>李晓峰</p>
</body>
</html>

p::after{
    content: '.';
    /*设置成块标签*/
    display: block;
    width: 100px;
    height: 100px;
    background-color: green;
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        p::first-letter{
            color: red;
        }
        p::before{
            content: '博客作者';
        }
        p::after{
            content: '.';
            /*设置成块标签*/
            display: block;
            /*width: 100px;*/
            /*height: 100px;*/
            /*background-color: green;*/
            /*visibility: hidden;*/
        }
    </style>
</head>
<body>
<p>李晓峰</p>
<div>nginx</div>
</body>
</html>

解决浮动带来的问题：

p::after{
    content: '.';
    /*设置成块标签*/
    display: block;
    /*width: 100px;*/
    /*height: 100px;*/
    /*background-color: green;*/
    visibility: hidden;
    height:0;
}

文字在中间显示：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css" media="screen">
        div p{
            color: red;
            text-align: center;
        }
    </style>
</head>
<body>
<div>
    <p>
        德国
    </p>
</div>
<p>sss</p>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css" media="screen">
        div p{
            color: red;
            width: 100px;
            font-size: 20px;
            background-color: green;
            text-align: center;
            line-height: 100px;
        }
    </style>
</head>
<body>
<div>
    <p>
        德国
    </p>
</div>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css" media="screen">
        div {
            color: red;
            width: 200px;
            background-color: green;
            text-align: center;
            line-height: 100px;
        }
        p{
            background-color: yellow;
        }
    </style>
</head>
<body>
<div>
    <p>
        德国
    </p>
</div>
</body>
</html>

（1）css的继承性：

继承来的属性权重为0，如果权重都为0，谁描述的近谁优先

#tt{}

.active{}

继承和权重

记住：有一些属性是可以继承下来： color 、 font-*、 text-*、line-* 。主要是文本级的标签元素。

但是像一些盒子元素属性，定位的元素（浮动，绝对定位，固定定位）不能继承。

盒模型：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        div{
            width: 200px;
            height: 200px;
            background-color: red;
            padding: 50px;
            border: 10px solid green;
        }
    </style>
</head>
<body>
<div>

</div>
</body>
</html>

border-top: 10px solid red;

border-right: 10px solid red;

border-bottom: 10px solid red;

border-left: 10pxb solid red;

举例：

Margin:(填坑)：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .box{
            width: 100px;
            height: 100px;
            background-color: red;
            margin-bottom: 50px;
        }
        .box2{
            width: 100px;
            height: 100px;
            background-color: yellow;
        }
    </style>
</head>
<body>
<div class="box">

</div>
<div class="box2"></div>
</body>
</html>

Margin 塌陷：

    .box{
        width: 100px;
        height: 100px;
        background-color: red;
        margin-bottom: 50px;
    }
    .box2{
        width: 100px;
        height: 100px;
        background-color: yellow;
        margin-top: 100px;
    }
</style>

span{
    background-color: #0000CC        }
.t{
    margin-right: 50px;
}
.f{
    margin-left: 30px;
}

注：：要写垂直距离在一个上面写不要写两个，水平的没问题

标准文档流：

（1）空白折叠现象

（2）高矮不齐，底边对齐

（3）自动换行，一行写不满，换行写

实例：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        *{
            padding: 0;
            margin: 0px;
        }
        div{
            width: 200px;
            height: 200px;
        }
        .box1{
            background-color: red;
        }
        .box2{
            background-color: green;
        }
        .box3{
            background-color: yellow;
        }
    </style>
</head>
<body>
<div class="box1">

</div>
<div class="box2">

</div>
<div class="box3">

</div>
</body>
</html>

    *{
        padding: 0;
        margin: 0px;
    }
    div{
        width: 200px;
        height: 200px;
    }
    .box1{
        background-color: red;
        float: left;
    }
    .box2{
        background-color: green;
        width: 230px;
    }
    .box3{
        background-color: yellow;
    }
</style>

贴边现象：

浮动的好处：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        *{
            padding: 0px;
            margin: 0;
        }
        .father{
            width: 1210px;
            height: 300px;
            margin: 0 auto;
            background-color: black;
        }
        .box1{
            background-color: red;
            height: 300px;
            width: 200px;
            float: left;
        }
        .box2{
            background-color: yellow;
            height: 230px;
            width: 200px;
            float: right;
        }
        .box3{
            background-color: green;
            height: 200px;
            width: 200px;
            margin: 0 auto;

        }
        .active{
            width: 1210px;
            height: 300px;
            background-color: purple;
            margin: 0 auto;
        }
    </style>
</head>
<body>
<div class="father">
    <div class="box1">
    1
</div>
<div class="box2">
    2
</div>
<div class="box3">
    3
</div>

</div>
<div class="active"></div>
</body>
</html>

Overflow：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        div{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            overflow:scroll;
        }
    </style>
</head>
<body>
<div>文字文字文字文字文字文字文字文字文字文字文
    字文字文字文字文字文字文字文字文字文字文字文字
    字文字文字文字文字文字文字文字文字文字文字文字
    字文字文字文字文字文字文字文字文字文字文字文字
    文字文字文字文字文字文字文字文字文字文字文字</div>
</body>
</html>

Margin:

如果漂浮的盒子不存在margin的塌陷

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
*{
    padding:0;
    margin: 0px;
}
        .head{
            width: 100%;
            height: 80px;
            background-color:black;
            padding-top: 20px;
        }
        .container{
            width: 1210px;
            margin: 0 auto;
            background-color: deeppink;

        }
        .head .logo{
            width: 50px;
            height: 50px;
            background-color:#ff6700;

        }
    </style>
</head>
<body>
<div class="head">
    <div class="container">
        <div class="logo">

        </div>
    </div>
</div>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
*{
    padding:0;
    margin: 0px;
}
        .head{
            width: 100%;
            height: 100px;
            background-color:black;
            /*padding-top: 20px;*/
        }
        .container{
            width: 1210px;
            margin: 0 auto;
            background-color:lawngreen;

        }
        .head .logo{
            width: 50px;
            height: 50px;
            background-color:#ff6700;
            float: left;
            margin-top: 20px;

        }
    </style>
</head>
<body>
<div class="head">
    <div class="container">
        <div class="logo">

        </div>
    </div>
</div>

</body>
</html>

总结漂浮的盒子是不能够margin 0 auto居中的

添加：

font-size: 30px;

调整字体大小

list-style: none;

去除圆点的

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        div{
            font-size: 30px;
            /*开头空两个字符*/
            text-indent: 2em;
            /*加下滑线*/
            text-decoration: underline;
            /*变成小手*/
            cursor: pointer;
            /*高度居中*/
            line-height: 40px;
            /*文本居中*/
            text-align: center;
        }
    </style>
</head>
<body>
<div>
    aaaddddf fdsfdsafsa efadsafasdf
</div>
</body>
</html>

border-radius: 50px;

这个是用来切园的可以100% 或者50%

Background 颜色：

Rgb表示法、十六进制表示法

Rgb：红色、蓝色、绿色三种原色组成

color: rgb(220,0,110);

图片平铺：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .jieyi{
            width: 1200px;
            height: 1000px;
            background-image: url("./jieyi.jpg");
        }
    </style>
</head>
<body>
<div class="jieyi">

</div>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .jieyi{
            width: 1200px;
            height: 1000px;
            background-image: url("./jieyi.jpg");
            /*不平埔 */
            background-repeat: no-repeat;
        }
    </style>
</head>
<body>
<div class="jieyi">

</div>
</body>
</html>

这个就是精灵图技术：

接下来切割圆形头像：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .jieyi{
            border: 1px solid red;
            /*想左和上面移动剩下的数值*/
            width: 200px;
            height: 200px;
            background-image: url("./jieyi.jpg");
            /*不平埔 */
            background-repeat: no-repeat;
            /*想左和上面移动的px*/
            background-position: -180px -100px;
            border-radius: 50%;
        }
    </style>
</head>
<body>
<div class="jieyi">

</div>
</body>
</html>

可以动态的去调整：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .jieyi{
            border: 1px solid red;
            /*想左和上面移动剩下的数值*/
            width: 200px;
            height: 200px;
            background-image: url("./jieyi.jpg");
            /*不平埔 */
            background-repeat: no-repeat;
            /*想左和上面移动的px*/
            /*background-position: -180px -100px;*/
            border-radius: 50%;
            background-attachment: fixed;
            margin-left: 150px;
            margin-top: 150px;
        }
    </style>
</head>
<body style="height: 2000px; width: 2000px">
<div class="jieyi">

</div>
</body>
</html>