Question

为了正确的CSS优先级设置，我搜索了一下，发现没有类似的排序。我很清楚地记得有人在很久以前的评论中发表了关于CSS优先权的帖子，但我完全不记得了。因此，我问这个问题 - 一方面，得到我的答案 - 并存档这个答案以供将来参考其他人（也包括我自己，这也会再次发生）。

这是我的片段：

.ContainerTitle {
  background: #fff;
  float: left;
  padding: 15px;
  padding-left: 15px;
  border: solid 1px #000;
  font-size: Large;
  color: #000;
  text-align: left;
  cursor: pointer;
  transition: all .1s ease-out;
}
.DownloadThis,
.ViewThis {
  display: inline-block;
  padding: 20px;
  padding-bottom: 10px;
  border: solid 1px #fff;
  width: 40px;
}
/*PROBLEM BELOW HERE HELP!!! */

.showHint {
  margin-top: 20px;
  background: #f1f1f1;
}
.ViewThis:hover .showHint:after {
  content: '*Hint: View Online';
}
.DownloadThis:hover .showHint:after {
  content: '*Hint: Download';
}
/*PROBLEM ABOVE HERE HELP!!! */

.DownloadThis {
  background: #1D9C73;
  color: #fff;
}
.ViewThis {
  background: #7D529E;
  color: #fff;
}
.DownloadThis:hover,
.ViewThis:hover {
  border: solid 1px #000;
  background: #fff;
}
.DownloadThis:hover {
  color: #1D9C73;
}
.ViewThis:hover {
  color: #7D529E;
}
.ContainerTitle:before,
.DownloadThis:before,
.ViewThis:before {
  font-family: FontAwesome;
  font-style: normal;
  font-weight: normal;
  text-decoration: inherit;
  padding-left: 6px;
  padding-right: 8px;
  font-size: 32px;
}
.ContainerTitle:before {
  content: '\f0f6';
  font-size: 24px;
}
.DownloadThis:before {
  content: '\f019';
}
.ViewThis:before {
  content: '\f06e';
}

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.1/css/font-awesome.min.css" rel="stylesheet" />
<div class="ContainerTitle">SYLLABUS:
  <div class="DownloadThis"></div>
  <div class="ViewThis"></div>
  <div class="showHint"></div>
</div>
<div class="ContainerTitle">NOTE:
  <div class="DownloadThis"></div>
  <div class="ViewThis"></div>
  <p class="showHint"></p>
</div>

当我将鼠标悬停在具有此代码的所需类上时，我希望在showHint类的帮助下显示Hint

.ViewThis:hover .showHint:after{content:'*Hint: View Online';}
.DownloadThis:hover .showHint:after{content:'*Hint: Download';}

但是，出于某种原因，无效！

我认为这是因为我搞砸了CSS设置中的优先级。

我希望它能达到与此相似的效果（但将鼠标悬停在 .DownloadThis 和 .ViewThis。 如果不同的通用消息< / strong>当我将鼠标悬停在 .ContainerTitle 上时，它也很棒！）：

.ContainerTitle { background: #fff; float: left; padding: 15px; padding-left: 15px; border: solid 1px #000; font-size: Large; color: #000; text-align: left; cursor: pointer; transition: all .1s ease-out; } .DownloadThis, .ViewThis { display: inline-block; padding: 20px; padding-bottom: 10px; border: solid 1px #fff; width: 40px; } .showHint { margin-top: 20px; background: #f1f1f1; } .ContainerTitle:hover .showHint:after { content: '*Hint: I want to display text like this!'; } .DownloadThis { background: #1D9C73; color: #fff; } .ViewThis { background: #7D529E; color: #fff; } .DownloadThis:hover, .ViewThis:hover { border: solid 1px #000; background: #fff; } .DownloadThis:hover { color: #1D9C73; } .ViewThis:hover { color: #7D529E; } .ContainerTitle:before, .DownloadThis:before, .ViewThis:before { font-family: FontAwesome; font-style: normal; font-weight: normal; text-decoration: inherit; padding-left: 6px; padding-right: 8px; font-size: 32px; } .ContainerTitle:before { content: '\f0f6'; font-size: 24px; } .DownloadThis:before { content: '\f019'; } .ViewThis:before { content: '\f06e'; }

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.1/css/font-awesome.min.css" rel="stylesheet" /> <div class="ContainerTitle">SYLLABUS: <div class="DownloadThis"></div> <div class="ViewThis"></div> <div class="showHint"></div> </div> <div class="ContainerTitle">NOTE: <div class="DownloadThis"></div> <div class="ViewThis"></div> <p class="showHint"></p> </div>

另外，我想知道为什么悬浮在.ContainerTitle上会无法正常工作.DownloadThis和.ViewThis？

答案是否与以下事实有关：.DownloadThis和.ViewThis是.ContainerTitle的chid？如果是这样，这种关系如何影响容器？我要求提供这些信息，以便将来不再重复同样的错误。

Answer 1

它不起作用，因为.showHint不是.ViewThis的后代。您需要使用general sibling selector (~)：

.ViewThis:hover ~ .showHint:after{content:'*Hint: View Online';}
.DownloadThis:hover ~ .showHint:after{content:'*Hint: Download';}

示例：

＆＃13;

.ContainerTitle {
  background: #fff;
  float: left;
  padding: 15px;
  padding-left: 15px;
  border: solid 1px #000;
  font-size: Large;
  color: #000;
  text-align: left;
  cursor: pointer;
  transition: all .1s ease-out;
}
.DownloadThis,
.ViewThis {
  display: inline-block;
  padding: 20px;
  padding-bottom: 10px;
  border: solid 1px #fff;
  width: 40px;
}
/*PROBLEM BELOW HERE HELP!!! */

.showHint {
  margin-top: 20px;
  background: #f1f1f1;
}
.ViewThis:hover ~ .showHint:after {
  content: '*Hint: View Online';
}
.DownloadThis:hover ~ .showHint:after {
  content: '*Hint: Download';
}
/*PROBLEM ABOVE HERE HELP!!! */

.DownloadThis {
  background: #1D9C73;
  color: #fff;
}
.ViewThis {
  background: #7D529E;
  color: #fff;
}
.DownloadThis:hover,
.ViewThis:hover {
  border: solid 1px #000;
  background: #fff;
}
.DownloadThis:hover {
  color: #1D9C73;
}
.ViewThis:hover {
  color: #7D529E;
}
.ContainerTitle:before,
.DownloadThis:before,
.ViewThis:before {
  font-family: FontAwesome;
  font-style: normal;
  font-weight: normal;
  text-decoration: inherit;
  padding-left: 6px;
  padding-right: 8px;
  font-size: 32px;
}
.ContainerTitle:before {
  content: '\f0f6';
  font-size: 24px;
}
.DownloadThis:before {
  content: '\f019';
}
.ViewThis:before {
  content: '\f06e';
}

＆＃13;

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.1/css/font-awesome.min.css" rel="stylesheet" />
<div class="ContainerTitle">SYLLABUS:
  <div class="DownloadThis"></div>
  <div class="ViewThis"></div>
  <div class="showHint"></div>
</div>
<div class="ContainerTitle">NOTE:
  <div class="DownloadThis"></div>
  <div class="ViewThis"></div>
  <p class="showHint"></p>
</div>

＆＃13;

Answer 2

你需要下一个兄弟和一般兄弟选择器。阅读它here。

＆＃13;

.ContainerTitle {
  background: #fff;
  float: left;
  padding: 15px;
  padding-left: 15px;
  border: solid 1px #000;
  font-size: Large;
  color: #000;
  text-align: left;
  cursor: pointer;
  transition: all .1s ease-out;
}
.DownloadThis,
.ViewThis {
  display: inline-block;
  padding: 20px;
  padding-bottom: 10px;
  border: solid 1px #fff;
  width: 40px;
}
/*PROBLEM BELOW HERE HELP!!! */

.showHint {
  margin-top: 20px;
  background: #f1f1f1;
}
.ViewThis:hover + .showHint:after {
  content: '*Hint: View Online';
}
.DownloadThis:hover ~ .showHint:after {
  content: '*Hint: Download';
}
/*PROBLEM ABOVE HERE HELP!!! */

.DownloadThis {
  background: #1D9C73;
  color: #fff;
}
.ViewThis {
  background: #7D529E;
  color: #fff;
}
.DownloadThis:hover,
.ViewThis:hover {
  border: solid 1px #000;
  background: #fff;
}
.DownloadThis:hover {
  color: #1D9C73;
}
.ViewThis:hover {
  color: #7D529E;
}
.ContainerTitle:before,
.DownloadThis:before,
.ViewThis:before {
  font-family: FontAwesome;
  font-style: normal;
  font-weight: normal;
  text-decoration: inherit;
  padding-left: 6px;
  padding-right: 8px;
  font-size: 32px;
}
.ContainerTitle:before {
  content: '\f0f6';
  font-size: 24px;
}
.DownloadThis:before {
  content: '\f019';
}
.ViewThis:before {
  content: '\f06e';
}

＆＃13;

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.1/css/font-awesome.min.css" rel="stylesheet" />
<div class="ContainerTitle">SYLLABUS:
  <div class="DownloadThis"></div>
  <div class="ViewThis"></div>
  <div class="showHint"></div>
</div>
<div class="ContainerTitle">NOTE:
  <div class="DownloadThis"></div>
  <div class="ViewThis"></div>
  <p class="showHint"></p>
</div>

＆＃13;

Answer 3

它不起作用，因为.showHint不是.DownloadThis或.ViewThis的孩子。

使用波浪号（普通兄弟）选择器，然后选择.showHint范围内的下一个（和所有）.ContainerTitle元素。

.ViewThis:hover ~ .showHint:after {
  content: '*Hint: View Online';
}
.DownloadThis:hover ~ .showHint:after {
  content: '*Hint: Download';
}

查看我的demo

CSS优先级搞砸了

这是我的片段：

3 个答案: