bootstrap embed-responsive 不适用于 css column-count。例如：
/** Divide the target element into <number> columns */
.columns {
-webkit-column-count: 4;
-webkit-column-gap: 10px;
/*-webkit-column-fill: auto;*/
-moz-column-count: 4;
-moz-column-gap: 10px;
/*-moz-column-fill: auto;*/
column-count: 4;
column-gap: 15px;
/*column-fill: auto;*/
}
.video-box {
border: 1px solid red;
}<link href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<div class="container">
<div class="columns">
<div class="video-box">
<!-- 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/qYv5R_e5hTM" frameborder="0" allowfullscreen></iframe>
</div>
</div>
<div class="video-box">
<!-- 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/feQ99SuGdsw" frameborder="0" allowfullscreen></iframe>
</div>
</div>
<div class="video-box">
<!-- 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/r_KEWddTrVc" frameborder="0" allowfullscreen></iframe>
</div>
</div>
</div>
</div>结果：
第二个和第三个视频没有显示！
任何想法为什么以及如何解决它？
笔记：
这似乎是 Chrome 上的一个错误。火狐没问题。