title: Nesting in css3
body: <p>I am very new to css and Sencha Touch 2. While working on some tutorial on Sencha Touch 2,I see a CSS file having code like </p>
  
  <pre><code>/* Increase height of list item so title and narrative fit */
  .x-list .x-list-item {
       min-height: 10.5em!important;
       height:7.5em;
  }
  /* Move the disclosure button up to account for the list item height increase */
  .x-list .x-list-disclosure {
       position: absolute;
       bottom: 4.0em;
       right: 0.10em;
  }
  </code></pre>
  
  <p>Is  <code>.x-list .x-list-item</code>   a css nesting concept and <code>x-list</code>  a class name?
  Also , is this concept purely a CSS concept or Sencha Touch concept?</p>