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CSS 特性

CSS 特性

作者: roy_pub | 来源:发表于2018-12-02 23:46 被阅读8次

    层叠性

    • 样式冲突,遵循就近原则
    • 样式不冲突,不会层叠
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>inherit</title>
        <style>
    
            p {
                color: green;
                font-size: 25px;
            }
    
            p {
                color: red;
            }
        </style>
    </head>
    <body>
        <div>
            <p>Hello World</p>
        </div>
    </body>
    </html>
    

    结果为红色25px的:Hello World

    继承性

    子标签会继承父标签的某些样式,一般和文本相关的会继承,比如文字颜色,大小,样式等。

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>inherit</title>
        <style>
            .inherit {
                color: cyan;
            }
        </style>
    </head>
    <body>
        <div class="inherit">
            <p>Hello world</p>
        </div>
    </body>
    </html>
    

    优先级

    优先级 权重
    * / 继承 0,0,0,0
    标签 0,0,0,1
    类,伪类 0,0,1,0
    id 0,1,0,0
    行内样式 1,0,0,0
    !important
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>inherit</title>
        <style>
            div {
                color: cyan;
            }
    
            .green {
                color: green;
            }
    
            #red {
                color: red;
            }
        </style>
    </head>
    <body>
        <div id="red" class="green">
            Hello World
        </div>
    </body>
    </html>
    

    结果为红色的:Hello World

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>inherit</title>
        <style>
            div {
                color: cyan;
            }
    
            .green {
                color: green!important;
            }
    
            #red {
                color: red;
            }
        </style>
    </head>
    <body>
        <div style="color: orange;" id="red" class="green">
            Hello World
        </div>
    </body>
    </html>
    

    结果为绿色的:Hello World

    权重相同,就近原则

    <!DOCTYPE html>
    <html lang="en">
    <head>
       <meta charset="UTF-8">
       <title>inherit</title>
       <style>
    
           p {
               color: green;
           }
    
           p {
               color: red;
           }
       </style>
    </head>
    <body>
       <div>
           <p>Hello World</p>
       </div>
    </body>
    </html>
    

    结果为红色的:Hello World

    权重会叠加

    • div ul li -> 0,0,0,3
    • .nav ul li -> 0,0,1,2
    • a:hover -> 0,0,1,1
    • .nav a -> 0,0,1,1
    • #nav p -> 0,1,0,1
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>inherit</title>
        <style>
    
            div p {
                color: green;
    
            }
    
            p {
                color: red;
            }
        </style>
    </head>
    <body>
        <div>
            <p>Hello World</p>
        </div>
    </body>
    </html>
    

    结果为绿色的:Hello World

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