记录每一次成长

html
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>伪元素遮罩层</title>
    <style>
        .content {
            width: 200px;
            height: 200px;
            border: 1px solid pink;
        }

        .content:after {
            content: "遮罩";
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            box-sizing: border-box;
            padding: 100px;
            background-color: rgba(0, 0, 0, .6);
            color: #fff;
            text-align: center;
        }

    </style>
</head>

<body>
    <div class="content">
        我是内容，我上面有一层遮罩
    </div>
</body>

</html>