Select 最后 3 children 根据 children 的数量

Question

我处于显示的元素数量可变的情况，我需要我无法实现的解决方案，我什至怀疑是否只有 CSS.

我只想在项目总数为 7 时对最后四项进行选择。我当前的 CSS 给出了 7 项的正确结果，但没有给出另一个数量的结果。

我怎样才能将其组合起来以查找 nth-last-child(7) 和 flex-item:nth-child(n+5)？

.flex-container {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
  padding: 0;
  margin: 0;
  list-style: none;
}

.flex-item {
  background: tomato;
  padding: 5px;
  width: 200px;
  height: 150px;
  margin-top: 10px;
  line-height: 150px;
  color: white;
  font-weight: bold;
  font-size: 3em;
  text-align: center;
}

.flex-item:first-child:nth-last-child(7),
.flex-item:first-child:nth-last-child(7)~.flex-item:nth-child(-n+4) {
  flex-basis: 23%;
}

.flex-item:nth-last-child(7)~.flex-item:nth-child(n+5) {
  flex-basis: 31%;
  background: blue;
}

<ul class="flex-container">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
  <li class="flex-item">6</li>
  <li class="flex-item">7</li>
</ul>

Answer 1

这是您要找的吗？

.flex-item:first-child:nth-last-child(7)

在只有 7 个项目时定位第一个 child，因此

.flex-item:first-child:nth-last-child(7)~.flex-item:nth-child(n+5)

只有当有7个项目时才会触发

.flex-container {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
  padding: 0;
  margin: 0;
  list-style: none;
}

.flex-item {
  background: tomato;
  padding: 5px;
  width: 200px;
  height: 150px;
  margin-top: 10px;
  line-height: 150px;
  color: white;
  font-weight: bold;
  font-size: 3em;
  text-align: center;
}

.flex-item:first-child:nth-last-child(7),
.flex-item:first-child:nth-last-child(7)~.flex-item:nth-child(-n+4) {
  flex-basis: 23%;
}

.flex-item:first-child:nth-last-child(7)~.flex-item:nth-child(n+5) {
  flex-basis: 31%;
  background: blue;
}

<ul class="flex-container">
  <li class="flex-item first">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
  <li class="flex-item">6</li>
  <li class="flex-item">7</li>
</ul>
<br/><br/>
<ul class="flex-container">
  <li class="flex-item first">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
  <li class="flex-item">6</li>
  <li class="flex-item">7</li>
  <li class="flex-item">8</li>
  <li class="flex-item">9</li>
  <li class="flex-item">10</li>
</ul>
<br/><br/>
<ul class="flex-container">
  <li class="flex-item first">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
</ul>

Select 最后 3 children 根据 children 的数量

Select last 3 children based on the number of children

html

css

css-selectors

siblings