title: How to maintain "gutter space" between "responsive" grid divs when they collapse?
body: <p>Im using the newest twitter bootstrap to construct a responsive grid website.  i have three divs across a responsive grid like so:</p>
  
  <pre><code>&lt;div class="row-fluid"&gt;
   &lt;div class="span4"&gt;...&lt;/div&gt;
   &lt;div class="span4"&gt;...&lt;/div&gt;
   &lt;div class="span4"&gt;...&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>...and this works as intended via the bootsrap documentation. However I have a separate background color on these divs from the html body background color, and when i drag the browser window to a smaller width to "collapse" the divs to show on top of each other, the gutter space between them disappears (creating a look of one big div versus three separate ones) is there anything i can do to create some gutter space between the divs when the width gets small enough to cause them to stack vertically?</p>