html - 如何在其中垂直和水平居中 div 的内容？

Question

我有一个投资组合类型 3 分栏布局。每个投资组合元素都是一个包含元素名称和一些简短内容的 div。首先显示元素名称，当我将鼠标悬停在 div 上时，div 翻转，然后显示简介。

当我将鼠标悬停在 div 上时，简报从左上角溢出。我希望元素名称和简介都放在 div 的正中央。以下是代码片段。

.flip-container {
  perspective: 1000;
  margin-right: 30px;
  background-color: red;
  margin-bottom: 20px;
}
/* flip the pane when hovered */

.flip-container:hover .flipper,
.flip-container.hover .flipper {
  transform: rotateY(180deg);
}
.flip-container,
.front,
.back {
  width: 360px;
  height: 320px;
}
/* flip speed goes here */

.flipper {
  transition: 0.6s;
  transform-style: preserve-3d;
  position: relative;
}
/* hide back of pane during swap */

.front,
.back {
  backface-visibility: hidden;
  position: absolute;
  text-align: center;
  /*top: 0;
	left: 0;*/
}
/* front pane, placed above back */

.front {
  z-index: 2;
  /* for firefox 31 */
  transform: rotateY(0deg);
}
/* back, initially hidden pane */

.back {
  transform: rotateY(180deg);
}

<div class="row">
  <div class="flip-container col-md-4 portfolio-item" ontouchstart="this.classList.toggle('hover');">
    <div class="flipper">
      <div class="front">
        <!-- front content -->
        <h3>
                        <a href="#">Project Name</a>
                      </h3>
      </div>
      <div class="back">
        <!-- back content -->
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam viverra euismod odio, gravida pellentesque urna varius vitae.</p>
      </div>
    </div>
  </div>
  <div class="flip-container col-md-4 portfolio-item" ontouchstart="this.classList.toggle('hover');">
    <div class="flipper">
      <div class="front">
        <!-- front content -->
        <h3>
                      <a href="#">Project Name</a>
                    </h3>
      </div>
      <div class="back">
        <!-- back content -->
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam viverra euismod odio, gravida pellentesque urna varius vitae.</p>
      </div>
    </div>
  </div>

Answer 1

您可以使用 flexbox为了这。将以下样式添加到您的 .front 和 .back div

CSS:

.front,
.back {
  backface-visibility: hidden;
  position: absolute;
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
}

这是一个working fiddle .