css不为人知的属性

相邻兄弟选择器之常用场景

https://user-gold-cdn.xitu.io/2019/7/29/16c3d4f579c4de52?imageslim

 

要使模态框背景透明，用rgba是一种简单方式

https://user-gold-cdn.xitu.io/2019/7/29/16c3d4fb360585bf?imageslim

 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body{
            height: 10000px;
        }
        .wrapper{
            display: flex;
            position: fixed;
            top: 0;
            left: 0;
            bottom: 0;
            right: 0;
            background-color: rgba(0, 0, 0, 0.3);
        }
        .box{
            background-color: red;
            width: 200px;
            height: 200px;
            margin: auto;
        }
    </style>
</head>
<body>
    <div class="wrapper">
        <div class="box">文字</div>
    </div>
</body>
</html>

　　

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body{
            height: 10000px;
        }
        .wrapper{
            display: flex;
            position: fixed;
            top: 0;
            left: 0;
            bottom: 0;
            right: 0;
        }
        .mask{
            position: fixed;
            top: 0;
            left: 0;
            bottom: 0;
            right: 0;
            /* background-color: rgba(0, 0, 0, 0.3); */
            background: black;
            opacity: 0.5;
        }

        .box{
            background-color: red;
            width: 200px;
            height: 200px;
            margin: auto;
        }
    </style>
</head>
<body>
    <div class="mask"></div>
    <div class="wrapper">
        <div class="box">文字</div>
    </div>
</body>
</html>

　　

posted @ 2020-12-02 20:16  xiaorain124  阅读(29)  评论(0)    收藏  举报