540 CSS3属性对层叠上下文的影响

impress

2020-10-07

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

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>CSS3属性对层叠上下文的影响1</title>
  <style type="text/css">
    /* 
      层叠上下文元素:  
      html、child  + parent
      parent  其实就是一个普通的块元素   块元素 > 定位 z-index:-1
    */

    /* 案例一分解 */
    .box {
      display: flex;
      text-align: center;
    }

    /* 【没有定位，普通的块元素】 */
    .parent {
      width: 200px;
      height: 100px;
      background: #168bf5;
      z-index: 1;
    }

    .child {
      width: 100px;
      height: 200px;
      margin-top: -20px;
      background: #32d19c;
      position: relative;
      z-index: -1;
      margin-left: 20px;
      color: #fff;
    }
  </style>
</head>

<body>
  <!-- 案例一分解:display:flex/inline-flex; -->
  <div class="box">
    <div class="parent">
      父元素
      <div class="child">子元素</div>
    </div>
  </div>
</body>

</html>

540 CSS3属性对层叠上下文的影响

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

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>CSS3属性对层叠上下文的影响2</title>
  <style type="text/css">
    /* 案例二分解*/
    .parent1 {
      width: 200px;
      height: 100px;
      background: #168bf5;
      opacity: .5;
    }

    .child1 {
      width: 100px;
      height: 200px;
      background: #32d19c;
      position: relative;
      z-index: -1;
    }
  </style>
</head>

<body>
  <!-- 案例二分解:opacity -->
  <div class="parent1">
    parent
    <div class="child1">child</div>
  </div>
</body>

</html>

540 CSS3属性对层叠上下文的影响

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

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>CSS3属性对层叠上下文的影响3</title>
  <style type="text/css">
    /* 案例三分解*/
    .parent3 {
      width: 200px;
      height: 100px;
      background: #168bf5;
      /* transform的值不为none就可以 */
      transform: rotate(5deg);
    }

    .child3 {
      width: 100px;
      height: 200px;
      background: #32d19c;
      position: relative;
      z-index: -1;
    }
  </style>
</head>

<body>
  <!-- 案例三分解:transform -->
  <div class="parent3">
    parent
    <div class="child3">child</div>
  </div>
</body>

</html>

540 CSS3属性对层叠上下文的影响

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

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>CSS3属性对层叠上下文的影响4</title>
  <style type="text/css">
    /* 案例四分解*/
    .parent4 {
      width: 200px;
      height: 100px;
      background: #168bf5;
      filter: blur(5px);
    }

    .child4 {
      width: 100px;
      height: 200px;
      background: #32d19c;
      position: relative;
      z-index: -1;
    }
  </style>
</head>

<body>
  <!-- 案例四分解:filter -->
  <div class="parent4">
    parent
    <div class="child4">child</div>
  </div>
</body>

</html>

540 CSS3属性对层叠上下文的影响