title: How can I fill an empty div partitioned using bootstrap grid system with a specific color?
body: <p>Consider this case</p>
  
  <pre><code>&lt;div class="row"&gt;
      &lt;div class="col-md-3 col-sm-3 col-xs-3"&gt;&lt;/div&gt;
      &lt;div class="col-md-6 col-sm-6 col-xs-6"&gt;&lt;/div&gt;
      &lt;div class="col-md-3 col-sm-3 col-xs-3"&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>In this case, suppose if I need to fill the first div (first column) within the parent div with a background of #FF0000 how can I do it? If I can do it in a regular way, that is by specifying the style="background-color:red", the background changes only for the content written within it. Not if I create another div inside it and set its height and width to 100% nothing happens. Why is it so? And how can I do it the correct way?</p>