Question

快速提问。如果我将鼠标悬停在一个孩子上以定位另一个孩子，或者将一个单独的div与另一个单独的div定位，过渡是否有效？

只有将孩子放在容器中并悬停在父母上方，我才能过渡到工作。有什么规则？

示例1（无效）：

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  justify-content: center;
}

.underline {
  width: 0px;
  height: 2px;
  background-color: black;
  transition: 0.4s;
}

h2:hover .underline {
  width: 165px;
}

<body>

    <h2>Hover Over Me</h2>
    <div class="underline"></div>

</body>

示例2（无效）

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  justify-content: center;
}

.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 50px;
}

.underline {
  width: 0px;
  height: 2px;
  background-color: black;
  transition: 0.4s;
}

h2:hover .underline {
  width: 165px;
}

<body>

  <div class="container">
    <h2>Hover Over Me</h2>
    <div class="underline"></div>
  </div>

</body>

示例3（可行）

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  justify-content: center;
}

.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 50px;
}

.underline {
  width: 0px;
  height: 2px;
  background-color: black;
  transition: 0.4s;
}

.container:hover .underline {
  width: 165px;
}

<body>

  <div class="container">
    <h2>Hover Over Me</h2>
    <div class="underline"></div>
  </div>

</body>

Answer 1

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  justify-content: center;
}

.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 50px;
}

.underline {
  width: 0px;
  height: 2px;
  background-color: black;
  transition:0.4s;
}

h2:hover + .underline {
  width: 165px;
}

<body>

  <div class="container">
    <h2>Hover Over Me</h2>
    <div class="underline"></div>
  </div>

</body>

您可以检查This中的CSS选择器

孩子之间的CSS过渡

1 个答案: