我正在使用 Bootstrap 4 alpha 2 并利用卡片。具体来说，我正在使用取自官方文档的这个示例。如何使所有卡片的高度相同？
我现在能想到的就是设置以下 CSS 规则：
.card {
min-height: 200px;
}
但这只是一个硬编码的解决方案，在一般情况下不起作用。我认为的代码与文档中的代码相同，即：
<div class="card-columns">
<div class="card">
<img class="card-img-top" data-src="..." alt="Card image cap">
<div class="card-block">
<h4 class="card-title">Card title that wraps to a new line</h4>
<p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
</div>
</div>
<div class="card card-block">
<blockquote class="card-blockquote">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
<footer>
<small class="text-muted">
Someone famous in <cite title="Source Title">Source Title</cite>
</small>
</footer>
</blockquote>
</div>
<div class="card">
<img class="card-img-top" data-src="..." alt="Card image cap">
<div class="card-block">
<h4 class="card-title">Card title</h4>
<p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
<p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
</div>
</div>
<div class="card card-block card-inverse card-primary text-xs-center">
<blockquote class="card-blockquote">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat.</p>
<footer>
<small>
Someone famous in <cite title="Source Title">Source Title</cite>
</small>
</footer>
</blockquote>
</div>
<div class="card card-block text-xs-center">
<h4 class="card-title">Card title</h4>
<p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
<p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
</div>
<div class="card">
<img class="card-img" data-src="..." alt="Card image">
</div>
<div class="card card-block text-xs-right">
<blockquote class="card-blockquote">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
<footer>
<small class="text-muted">
Someone famous in <cite title="Source Title">Source Title</cite>
</small>
</footer>
</blockquote>
</div>
<div class="card card-block">
<h4 class="card-title">Card title</h4>
<p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.</p>
<p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
</div>
</div>
