title: Set space between divs
body: <p>I have two divs like this:</p>
  <pre><code>&lt;section id=&quot;main&quot;&gt;
    &lt;div id=&quot;left&quot;&gt;
      &lt;asp:ContentPlaceHolder ID=&quot;left&quot; runat=&quot;server&quot; /&gt;
    &lt;/div&gt;
    &lt;div id=&quot;right&quot;&gt;
      &lt;asp:ContentPlaceHolder ID=&quot;right&quot; runat=&quot;server&quot; /&gt;
    &lt;/div&gt;
  &lt;/section&gt;
  </code></pre>
  <p>And here is my css:</p>
  <pre><code>#left {
    float: left;
    margin-right: 17px;    
  }
  
  #right {
    float: right;
  }
  </code></pre>
  <p>I want the space between the divs to be <code>40px</code>. I tried adding padding, margin and width in my css, but I think it didn't set the padding to correct <code>40px</code>. How to do it?</p>