How to maintain dynamically added Menu design stable after click on SubMenu using C# in ASP.Net

Means i havea menu when i click on it sub menu will open but the problem is second menu name aslo comee down with it click.this is the original image without any click on menu.so wehn i click on drama ronak will also come down with dram submenu.

Like this i want that when i clic dram ronak will not coem down and whn i click ronak vice-versa

  private void getTopic()
    {
        clsTopic objTopic = new clsTopic(true);
        objTopic.SelectAll();

        clsArtical objArtical = new clsArtical(true);
        objArtical.SelectAll();
        int i = 0;
        int j = 0;
        int k = 1;
        int m = 1;

        string str = string.Empty;

        for (i = 0; i < objTopic.ListclsTopic.Count; i++)
        {
            //str += @"<input id='tab1' type='radio' name='tabs' checked>
            //    <label for='tab1'>
            //    <i class=''>" + objTopic.ListclsTopic[i].TopicID + "</i><span>" + objTopic.ListclsTopic[i].TopicName + "</span></label>";

            str += @"<input id=" + "tab" + k + @" type='radio' name='tabs' checked>
               <label for=" + "tab" + k + @">
               <i class=''>" + objTopic.ListclsTopic[i].TopicID + "</i><span>" + objTopic.ListclsTopic[i].TopicName + "</span></label>";
            k++;

            for (j = 0; j < objArtical.ListclsArtical.Count; j++)
            {
                if (objTopic.ListclsTopic[i].TopicID == objArtical.ListclsArtical[j].TopicID)
                {
                    str += @"<section id=" + "content" + m + @" class='tab-content11'>
                           <p><a href='#'>" + "»" + objArtical.ListclsArtical[j].ArticalName + @"</a></p></section>";
                    //  m++;
                                    }
            }
            m++;
        }
        tabdata.InnerHtml = str;
    }
}

 <div>
        <div class="row">
            <%--<div class="tab_container1">
                <div id="menu" runat="server">
                </div>
            </div>--%>
            <div class="tab_container1" id="tabdata" runat="server">
            </div>
        </div>
    </div>