title: What do '>' and '&' mean in less.js?
body: <p>I am going through bootstrap's less code. I am curious what do '>' and '&amp;' mean in defining css class?</p>
  
  <pre><code>  .navbar-nav {                                                                           
      &gt; li &gt; a {                                                                            
        color: @navbar-custom-link-color;                                                   
  
        &amp;:hover,                                                                            
        &amp;:focus {                                                                           
          color: @navbar-custom-link-hover-color;                                           
        }                                                                                   
      }                                                                                     
      &gt; .active &gt; a {                                                                       
        &amp;,                                                                                  
        &amp;:hover,                                                                            
        &amp;:focus {                                                                           
          color: @navbar-custom-link-active-color;                                          
        }                                                                                   
      }                                                                                     
      &gt; .disabled &gt; a {                                                                     
        &amp;,                                                                                  
        &amp;:hover,                                                                            
        &amp;:focus {                                                                           
          color: @navbar-default-link-disabled-color;                                       
          background-color: @navbar-default-link-disabled-bg;                               
        }                                                                                   
      }                                                                                     
    } 
  </code></pre>
  
  <p>Is there any detailed tutorial for less.js that I can refer?</p>