html - 父 div 采用第一个子元素的高度而不是所有子元素高度的总和

Question

父 div“ block ”有一个position:relative。它不会自动扩展以假定其子项总高度的高度，而是仅占用第一个子项的高度。您能解释一下为什么会发生这种情况以及如何应对吗？

    .grid {
      position: relative;
      z-index: 1;
      float: left;
      margin: 3px;
    }
    .grid a {
      text-decoration: none;
    }
    .grid .p7 {
      width: 240px;
      height: 300px;
      border: 1px solid crimson;
    }
    .blocks {
      position: relative;
    }
    .blocks .heading a {
      text-decoration: none;
    }
    .blocks .heading a h3 {
      text-transform: uppercase;
      font-size: 28px;
      font-family: "Rokkitt";
      font-weight: 700;
      padding: 0 3px;
      line-height: 26px;
      color: #222;
      text-align: center;
    }
    .blocks .heading a p {
      font-size: 16px;
      font-family: "Rokkitt";
      font-weight: 400;
      padding: 5px 3px 10px;
      color: #333;
      text-align: center;
    }

<div class="blocks">
  <div class="heading">
    <a href="">
      <h3>Featured Deals</h3>
      <p>Hand selected by our creative director</p>
    </a>
  </div>
  <div class="grid">
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
  </div>
</div>

Answer 1

您需要清除 .grid div 上的 float ，否则该 div 的高度将不计入边距。

一种方法是使用overflow:hidden 但还有其他方法，详见HERE

.grid {
  position: relative;
  z-index: 1;
  float: left;
  margin: 3px;
}
.grid a {
  text-decoration: none;
}
.grid .p7 {
  width: 240px;
  height: 300px;
  border: 1px solid crimson;
}
.blocks {
  position: relative;
  background: #bada55;
  overflow: hidden;
  /* here */
}
.blocks .heading a {
  text-decoration: none;
}
.blocks .heading a h3 {
  text-transform: uppercase;
  font-size: 28px;
  font-family: "Rokkitt";
  font-weight: 700;
  padding: 0 3px;
  line-height: 26px;
  color: #222;
  text-align: center;
}
.blocks .heading a p {
  font-size: 16px;
  font-family: "Rokkitt";
  font-weight: 400;
  padding: 5px 3px 10px;
  color: #333;
  text-align: center;
}

<div class="blocks">
  <div class="heading">
    <a href="">
      <h3>Featured Deals</h3>
      <p>Hand selected by our creative director</p>
    </a>
  </div>
  <div class="grid">
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
    <a href="details.html">
      <div class="grid p7"></div>
    </a>
  </div>
</div>