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HTML 

              
                <!-- Wrapper Start -->
<div class="wrapper748 center padding-40 light-silver">
  <p class="margin-bottom text-red">
  <code>Click the plus <i class="fa fa-plus-square-o mr"></i> icon next to the folder you want to expand.</code>
  </p>
  <p class="margin-bottom text-red">
  <code>Click the minus <i class="fa fa-minus-square-o mr"></i> icon next to the folder you want to collapse.</code>
  </p>
  
<!-- Treeview Start -->
<ul class="treeview">
  
 <!-- Main Folder Start -->
  <li class="extend">
    
    
    <label class="folder">
      <input type="checkbox" name="extend" checked>
      <i>Your Project</i>
      <ul>
        <li class="file">index.html</li>
        <!-- Css Folder Start -->
        <li class="extend">
          
          <label class="folder">
            <input type="checkbox" name="extend" checked>
            <i>css</i>
            <ul>
              <li class="file">modulr.css</li>
              
              <!-- Core Modulr Folder Start -->
              <li class="extend">
                <label class="folder">
                  <input type="checkbox" name="extend">
                  <i>core</i>
                  <ul>
                    <li class="file">reset.css</li>
                    <li class="file">typography.css</li>
                    <li class="file">info.css</li>
                    <li class="file">grid.css</li>
                    <li class="file">form.css</li>
                    <li class="file">button.css</li>
                    <li class="file">list.css</li>
                    <li class="file">table.css</li>
                    <li class="file">navigation.css</li>
                    <li class="file">color.css</li>
                    <li class="file">animation.css</li>
                    <li class="file">modifier.css</li>
                    <li class="file">responsive.css</li>
                  </ul>
                </label>
              </li>
              <!-- Core Modulr Folder End -->
              
              <!-- Modules Folder Start -->
              <li class="extend">
                <label class="folder">
                  <input type="checkbox" name="extend">
                  <i>modules</i>
                  <ul>
                    <li class="extend">
                      <label class="folder">
                        <input type="checkbox" name="extend" checked>
                        <i>your-module</i>
                        <ul>
                          <li class="file">main.css</li>
                          <li class="file">modifier.css</li>
                        </ul>
                      </label>
                    </li>
                  </ul>
                </label>
              </li>
              <!-- Modules Folder End -->
            </ul>
          </label>
          
        </li>
        <!-- Css Folder End -->
      </ul>
    </label>
    
  </li>
  <!-- Main Folder End -->
  
</ul>
<!-- Treeview End -->

</div>
!

CSS 

              
                /*
  Modulr.css
  ---------------------
  @desc: Modular CSS Framework
  @author: Decorator.io
  @twitter: https://www.twitter.com/_uloga
  @source: http://www.decorator.io/modulr
\--------------------------------------------*/

/* __ modulr.css module : treeview __ */

.treeview{
  line-height: 28px;
  font-weight: 500;
  font-size: 15px;
}
.treeview,
.treeview ul,
.treeview ul li{
  width: 100%;
  float: left;
}
.treeview .folder{
  position: relative;
}
.treeview .folder i{
  padding-left: 22px;
}
.treeview .folder:before,
.treeview .file:before,
.treeview .external:before{
  font-family:'FontAwesome';
  float: left;
  margin-right: 6px;
}
.treeview .folder:before{
  content: "\f114";
  position: absolute;
  left: 17px;
  font-size: 17px;
}
.treeview .file:before{
  font-size: 90%;
  content: "\f016"
}
.treeview .external:before{
  font-size: 90%;
  content: "\f122";
}
.treeview .extend .folder > ul{
  display: none;
  margin-left: 18px;
}
.treeview .extend label{
  float: left;
}
.treeview .extend input{
  display: none;
}
.treeview .extend input[type=checkbox] + i:before {
  content: "\f196";
  color: #111;
  float: left;
  font-size: 14px;
  margin-left: 1px;
  margin-top: 7px;
  cursor: pointer;
}
.treeview .extend input[type=checkbox]:checked + i:before{
  content: "\f147";
}
.treeview .extend input[type=checkbox]:checked ~ ul{
  display: block;
}
!

JS
!
999px

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