css外边距margin的塌陷问题

子级元素的外边距margin同时也会影响到父级元素，这就是css外边距的塌陷问题。

举个例子：

<!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>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      text-decoration: none;
    }
    div {
      background-color: pink;
      height: 100px;
      width: 100px;
    }
    div.father {
      background-color: pink;
    }
    div.child {
      /* margin-top: 80px; */
      background-color: orange;
      height: 50px;
      width: 50px;
    }
  </style>
</head>
<body>
  <div class="father">
    <div class="child">child</div>
  </div>
 
</body>
</html>

显示的结果为：

当在子级元素设置外边距时，会同时影响到父级元素：

<!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>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      text-decoration: none;
    }
    div {
      background-color: pink;
      height: 100px;
      width: 100px;
    }
    div.father {
      background-color: pink;
    }
    div.child {
      margin-top: 80px;
      background-color: orange;
      height: 50px;
      width: 50px;
    }
  </style>
</head>
<body>
  <div class="father">
    <div class="child">child</div>
  </div>
  
</body>
</html>

解决办法：

  1. 父级元素控制内边距即可。
  2. 父级元素添加overflow字段取值为hidden
<!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>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      text-decoration: none;
    }
    div {
      background-color: pink;
      height: 100px;
      width: 100px;
    }
    div.father {
      padding-top: 25px;
      background-color: pink;
    }
    div.child {
      /* margin-top: 80px; */
      background-color: orange;
      height: 50px;
      width: 50px;
    }
  </style>
</head>
<body>
  <div class="father">
    <div class="child">child</div>
  </div>
  
</body>
</html>

posted @ 2022-04-09 12:06  Kisen  阅读(42)  评论(0)    收藏  举报