javascript - 我怎样才能水平居中 3 div？

Question

所以我有 3 张卡片，我要把我的元素放在里面，我需要它们完全水平居中。我尝试了很多东西，但到目前为止都没有奏效。

这是卡片的代码。

.card {
  background: #fff;
  border-radius: 3px;
  display: inline-block;
  height: 300px;
  margin: 1rem;
  position: relative;
  width: 290px;
  overflow: hidden;
  opacity: 1;
}

.card .topImage {
  display: inline-flex;
  width: 100%;
  height: 220px;
  overflow: hidden;
  align-content: center;
}

.topImage {
    background-color: rgba(0, 0, 0, .3);
}

.card .topImage img {
  height: 220px;
}

.card .bottom {
  height: 80px;
  width: 100%;
}

.card .bottom p {
  text-align: left;
  height: 80px;
  width: 100%;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  padding-left: 20px;
  display: flex;
  align-items: center;
  text-decoration: none;
  color: #444;
  font-size: 18px;
  font-family: Roboto, sans-serif;
}

.card-1 {
  box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
  transition: all 0.3s cubic-bezier(.25,.8,.25,1);
}

.card-1:hover {
  box-shadow: 0 14px 28px rgba(0,0,0,0.25), 0 10px 10px rgba(0,0,0,0.22);
  cursor: pointer;
}

    <div class="card card-1">
  <div class="topImage">
  </div>
  <div class="bottom">
    <p>Project 1</p>
  </div>
</div>

<div class="card card-1">
  <div class="topImage">
  </div>
  <div class="bottom">
    <p>Project 2</p>
  </div>
</div>

<div class="card card-1">
  <div class="topImage">
  </div>
  <div class="bottom">
    <p>Project 3</p>
  </div>
</div>

Answer 1

就用flexbox吧。为卡片制作一个容器并放置 display: flex;在其上，然后 justify-content: center 将它们居中，无论新容器 div 的大小如何

    .card {
      background: #fff;
      border-radius: 3px;
      display: inline-block;
      height: 300px;
      margin: 1rem;
      position: relative;
      width: 290px;
      overflow: hidden;
      opacity: 1;
    }

    .card .topImage {
      display: inline-flex;
      width: 100%;
      height: 220px;
      overflow: hidden;
      align-content: center;
    }

    .topImage {
        background-color: rgba(0, 0, 0, .3);
    }

    .card .topImage img {
      height: 220px;
    }

    .card .bottom {
      height: 80px;
      width: 100%;
    }

    .card .bottom p {
      text-align: left;
      height: 80px;
      width: 100%;
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      padding-left: 20px;
      display: flex;
      align-items: center;
      text-decoration: none;
      color: #444;
      font-size: 18px;
      font-family: Roboto, sans-serif;
    }

    .card-1 {
      box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
      transition: all 0.3s cubic-bezier(.25,.8,.25,1);
    }

    .card-1:hover {
      box-shadow: 0 14px 28px rgba(0,0,0,0.25), 0 10px 10px rgba(0,0,0,0.22);
      cursor: pointer;
    }

    .card-container {
       display: flex;
       justify-content: center;
    }

<div class="card-container">

    <div class="card card-1">
      <div class="topImage">
      </div>
      <div class="bottom">
        <p>Project 1</p>
      </div>
    </div>

    <div class="card card-1">
      <div class="topImage">
      </div>
      <div class="bottom">
        <p>Project 2</p>
      </div>
    </div>

    <div class="card card-1">
      <div class="topImage">
      </div>
      <div class="bottom">
        <p>Project 3</p>
      </div>
    </div>

</div>