旋转木马的高度和宽度不会改变

Question

嗨所以这是代码

<div id='mai'>
  <div class="jumbotron">
  <div class="container">
   <div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
  <!-- Indicators -->
  <ol class="carousel-indicators">
    <li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
    <li data-target="#carousel-example-generic" data-slide-to="1"></li>
    <li data-target="#carousel-example-generic" data-slide-to="2"></li>
  </ol>

  <!-- Wrapper for slides -->
  <div class="carousel-inner" role="listbox">
    <div class="item active">
      <img src="img/2.jpg" alt="">
      <div class="carousel-caption">
        ...
      </div>
    </div>
    <div class="item">
      <img src="img/3.jpg" alt="">
      <div class="carousel-caption">
        ...
      </div>
    </div>
    ...
  </div>

  <!-- Controls -->
  <a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
    <span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
    <span class="sr-only">pre</span>
  </a>
  <a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
    <span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
    <span class="sr-only">nx</span>
  </a>
</div>

  </div>
</div>
</div>

<h3>Example heading <span class="label label-default">New</span></h3>

<div class="row">
  <div class="col-sm-6 col-md-4">
    <div class="thumbnail">
      <img src="img/4.jpg" alt="..">
      <div class="caption">
        <h3>برنده لوح تقدیر</h3>
        <p>...</p>
        <p><a href="#" class="btn btn-primary" role="button">Button</a> <a href="#" class="btn btn-default" role="button">Button</a></p>
      </div>
    </div>
  </div>
    <div class="col-sm-6 col-md-4">
    <div class="thumbnail">
      <img data-src="holder.js/300x300" alt="...">
      <div class="caption">
        <h3>Thumbnail label</h3>
        <p>...</p>
        <p><a href="#" class="btn btn-primary" role="button">Button</a> <a href="#" class="btn btn-default" role="button">Button</a></p>
      </div>
    </div>
  </div>
    <div class="col-sm-6 col-md-4">
    <div class="thumbnail">
      <img data-src="holder.js/300x300" alt="...">
      <div class="caption">
        <h3>Thumbnail label</h3>
        <p>...</p>
        <p><a href="#" class="btn btn-primary" role="button">Button</a> <a href="#" class="btn btn-default" role="button">Button</a></p>
      </div>
    </div>
  </div>
</div>

我试图用类mai改变高度和宽度，但它不会改变我的旋转木马div高度，它会打破我的缩略图并将它们向上朝向主旋转木马... 我该怎么办 ？？？？