Dynamically adding controls on a hierarchical structure on MVC

/*
 * Note: While Microsoft is not the author of this file, Microsoft is
 * offering you a license subject to the terms of the Microsoft Software
 * License Terms for Microsoft ASP.NET Model View Controller 3.
 * Microsoft reserves all other rights. The notices below are provided
 * for informational purposes only and are not the license terms under
 * which Microsoft distributed this file.
 *
 * jQuery UI CSS Framework 1.8.11
 *
 * Copyright 2011, AUTHORS.txt (http://jqueryui.com/about)
 *
 * http://docs.jquery.com/UI/Theming/API
 */

/* Layout helpers
----------------------------------*/
.ui-helper-hidden { display: none; }
.ui-helper-hidden-accessible { position: absolute !important; clip: rect(1px 1px 1px 1px); clip: rect(1px,1px,1px,1px); }
.ui-helper-reset { margin: 0; padding: 0; border: 0; outline: 0; line-height: 1.3; text-decoration: none; font-size: 100%; list-style: none; }
.ui-helper-clearfix:after { content: "."; display: block; height: 0; clear: both; visibility: hidden; }
.ui-helper-clearfix { display: inline-block; }
/* required comment for clearfix to work in Opera \*/
* html .ui-helper-clearfix { height:1%; }
.ui-helper-clearfix { display:block; }
/* end clearfix */
.ui-helper-zfix { width: 100%; height: 100%; top: 0; left: 0; position: absolute; opacity: 0; filter:Alpha(Opacity=0); }


/* Interaction Cues
----------------------------------*/
.ui-state-disabled { cursor: default !important; }


/* Icons
----------------------------------*/

/* states and images */
.ui-icon { display: block; text-indent: -99999px; overflow: hidden; background-repeat: no-repeat; }


/* Misc visuals
----------------------------------*/

/* Overlays */
.ui-widget-overlay { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }