Question

伙计们，我是HTML和CSS的初学者，当我尝试选择另一个类中的类时，只是遇到了困惑。也就是说，正如您在下面的代码中看不到的那样，我正在尝试定位位于容器类内部的.num1类。问题是为什么当我直接定位.num1时，什么都没发生，而是定位.container .num1 {}时，一切正常。我不能直接定位num1吗？

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    .container{
        background: lightcoral;
       display: flex;
       justify-content: center;
       align-items: stretch;
    }
    .container>div{
        background: red;
        border:3px solid black;
        width: 150px;
        height: 150px;

    }

    .num1{
        height: 300px;
    }

    </style>
</head>
<body>
    <div class="container">
        <div class="item num1">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
        <div class="item">6</div>
    </div>
</body>
</html>

Answer 1

您应该这样使用.container .num1

   .container{
        background: lightcoral;
       display: flex;
       justify-content: center;
       align-items: stretch;
    }
    .container div{
        background: red;
        border:3px solid black;
        width: 150px;
        height: 150px;

    }

    .container .num1 {
        height: 300px;
    }

 <div class="container">
    <div class="item num1">1</div>
    <div class="item">2</div>
    <div class="item">3</div>
    <div class="item">4</div>
    <div class="item">5</div>
    <div class="item">6</div>
</div>

希望此表对您有所帮助。

Answer 2

了解CSS样式优先级https://www.thebookdesigner.com/2017/02/styling-priorities-css-for-ebooks-3/

.container{
   background: lightcoral;
   display: flex;
   justify-content: center;
   align-items: stretch;
}
.container>div{
    background: red;
    border:3px solid black;
    width: 150px;
    height: 150px;

}

.container .num1{
    height: 300px;
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div class="container">
        <div class="item num1">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
        <div class="item">6</div>
    </div>
</body>
</html>

为什么在班级内部选择班级不起作用

2 个答案: